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Full text of "Radio for all"

THE LIBRARY 

OF 

THE UNIVERSITY 
OF CALIFORNIA 

LOS ANGELES 



RADIO FOR ALL 



THE FUTURE OF RADIO 

IN this illustration are shown some of the future wonders of Radio. Several 
of the ideas are already in use, in an experimental way, and it should not be 
thought that the entire conception is fantastic. 

The illustration shows a business man, let us say, fifty years hence. To the 
right is a television and automatic radiophone. By means of the plug shown 
to the right of the machine, the man can plug in any city in the United States 
he desires ; then, by means of this automatic control board he can select anv 
number in that city he wishes, merely by consulting his automatic telephone 
directory. As soon as he has obtained his number, a connection is made auto- 
matically and he not only can talk, but he can see the party whom he calls. At 
the top of the instrument is a loud-talker which projects the voices of the people, 
while on a ground-glass in front of him the distant party is made visible. This 
idea is already in use, experimentally. 

Directly in front of the man, we see the "radio business control." By means of 
another television scheme, right in back of the dial, the man, if he chooses to do 
so, can load and unload a steamer, all by radio telemechanics, or throw a distant 
switch, or if a storm comes up, look into the interior of his apartment and then, 
merely by pressing a key, pull down the windows; all of which can be accom- 
plished by radio telemechanics, a science already well known. 

His business correspondence comes in entirely by radio. There is a tele- 
radio-typewriter. This electro-magnetic typewriter can be actuated by any one 
who chooses to do so. For instance, if we wish to write a letter to Jones & 
Company, Chicago, Illinois, we call up by radio, that station, and tell the operator that 
we wish to write a letter to the Company. Once the connection is established, 
the letter is written in New York, let us say, on a typewriter, and automatically 
sent out through space by radio; letter for letter, word for word being written 
by the other typewriter in Chicago. The letter when finished falls into a basket. 
Instead of sending our correspondence by mail we shall then do our letter-writing 
by radio. There is nothing difficult about this scheme, and as a matter of fact, it can 
be put into use today, if so desired. We have all the instrumentalities ready. 

Going further, we find the Radio Power Distributor Station that sends out 
power over a radius of 100 miles or more. This radio power may be used for 
lighting, and other purposes. 

In front of the bridge we see a number of people who are propelled by 
Radio Power Roller Skates. On their heads we see curious 3-prong metallic 
affairs. These collect the radio power from a nearby railing, which, however, is 
not in view, and which they do not touch. The power is sent through space from 
the rail to the 3-pronged affair and then is conveyed to the skates, which are 
operated by small electric motors. The<e roll at the rate of 15 to 20 miles an 
hour, and there is no visible connection between the wearer and the Radio 
Power Distributor. 

We next see the crewless ships controlled by radio. This has been made pos- 
sible today. Indeed, several U. S. battleships have already been manoeuvred over 



a considerable distance by radio. The time will come when we can direct a ship 
across the ocean without a human being on board. Future freight will be sent 
in this manner. The ship, every ten minutes, gives its location by radio, so that 
the land dispatcher will know at any time where the ship is located. Collisions 
are avoided by a number of instruments into details of which we need not go here, 
but which have already been perfected. Collision with icebergs also is avoided 
by thermo-couples which divert the ship away from the iceberg as soon as it 
enters water which has been cooled below a certain degree. 

The radio-controlled airplane works similarly to the radio-controlled ship, 
and it will be possible to control such airships very readily in the future. As a 
matter of fact, John Hays Hammond, Jr., in this country, has done this very 
thing. Radio-controlled airplanes will play a great role in the next war. 

It is a mistake to think that radio is only good for the distribution of intel- 
ligence. As the illustration shows, the great uses of radio have not been touched 
upon as yet. 

THE AUTHOR. 



RADIO FOR ALL 



BY 

H. GERNSBACK 

EDITOR OF "RADIO NEWS" 



WITH 13 HALFTONES AND 138 ILLUSTRATIONS 




PHILADELPHIA & LONDON 
J. B. LIPPINCOTT COMPANY 

1922 



COPYRIGHT, 1923, BY J. B. LIPPINCOTT COMPANY 



PRINTED BY J. B. LIPPINCOTT COMPANY 

AT THE WASHINGTON SQUARE PRESS 

PHILADELPHIA, U, S, A, 



TK 



PREFACE 

IN writing the present volume the author has 
continually had in mind a book for the public at 
large, not acquainted as yet with the radio art. 
After having reviewed nearly all the recent books 
on radio that have appeared since radio took 
the public's fancy, the author believes that the 
present volume covers ground not touched upon by 
other writers. 

The keynote of the book has been simplicity in 
language, and simplicity in radio. This book, 
therefore, is not a technical volume, and wherever 
possible all technicalities, all mathematics, and all 
abstruse subjects have been left out entirely. It will 
also be noted that the author has not made 
use of the word "ether" in this book; for the 
reason that modern scientists are no longer 
in sympathy with the ether theory. The vacuum 
tube, it will be noted, has been touched upon very 
lightly and only where it was absolutely necessary. 
The reason is that the vacuum tube is a highly tech- 
nical subject, and therefore does not belong in this 
book. It is a science by itself. 

The author has always been a great believer in 
analogies to drive a point home ; and for this reason 
analogies have been made use of freely wherever 
possible in this volume. 



12755CO 



6 PREFACE 

His experience in editing the first radio 
journal in the United States, Modern Electrics, 
in 1908, then later, Electrical Experimenter, (now 
Science and Invention), and, still more recently, as 
editor of Radio News, has given him the opportunity 
to view the radio problem through the eyes of the 
"man in the street." He hopes that he has suc- 
ceeded in conveying a technical message into 
plain English. 

If the present volume is the means of converting 
a fair percentage of the public at large to radio, 
the labor expended has been well worth while. 

H. GERNSBACK 
New York, June, 1922 



CONTENTS 



CHAPTER PAGE 

I. HISTORIC 11 

II. WAVE ANALOGIES 15 

III. TRANSMITTING (GENERAL) 30 

IV. RECEIVING (GENERAL) 42 

V. RECEIVING INSTRUMENTS 51 

VI. TUNING 101 

VII. AERIALS, LOOP AERIALS, GROUNDS 108 

VIII. RADIO DIAGRAMS AND How TO READ THEM 149 

IX. RADIO TELEPHONY 164 

X. How TO MAKE SIMPLE RECEIVING OUTFITS 180 

XI. THE FUTURE OF RADIO 229 

XH. RADIO ACT pyj912.... 239 

.. 283 



LIST OF ILLUSTRATIONS 

The Future of Radio Frontispiece 

Transmitting President Harding's Arlington Address 42 

Amplifiers Used to Receive the Speech 42 

Motorbus Equipped With Radio 70 

Two Portraits Transmitted by Radio 101 

The Author's Radiotrola 127 

Mme. Olga Petrova Singing for Radio 149 

Mme. Gadski Singing Tannhauser Aria 164 

Broadcasting Station Power Plant 173 

Author Delivering Lecture From Newark 229 

Power Plant of Newark Broadcasting Station 239 

Map U. S. Radio Broadcasting Stations 282 



RADIO FOR ALL 

CHAPTER I 
HISTORIC 

LET us begin at the beginning. There are so 
many misconceptions in radio today that it is best 
that the reader should know just how the art of 
radio came into existence. The true art of radio 
was unquestionably discovered by Heinrich Hertz, 
a German professor, living at Frankfort. His first 
technical papers on his epoch-making invention were 
published in 1887. Hertz's experiments were chiefly 
made in the laboratory. Years before, Maxwell had 
made the statement that light waves and electric 
waves were all of the same order. There had, 
however, before Hertz's time never been any experi- 
ments of electric waves in free space. Hertz was 
the first to send electric waves through space 
by means of an electric spark. His appara- 
tus was simple; he had an electric spark coil that 
made intermittent sparks, and by proper arrange- 
ment of this station, he could receive sparks at a 
distance by the simple arrangement of cutting a 
single wire hoop and leaving a small gap. Between 
the two free ends, small sparks jumped whenever 
sparks were made to jump on his spark coil a few 
yards away. In other words, every time he pressed 

11 



13 RADIO FOR ALL 

the key at his sending station, a spark would jump 
at the small gap at his receiving station, which was 
composed of nothing but a wire hoop. This con- 
clusively proved that electric or, better, electro- 
magnetic waves had been sent through free space. 
His were only laboratory experiments, and while 
he described the phenomenon correctly in scientific 
papers, and while it was even in these days consid- 
ered an epoch-making discovery, no one thought 
of using the invention for practical purposes. 

However, Guglielmo Marconi, an Italian youth 
had read of these experiments, and being gifted 
along these lines, he duplicated Hertz's experiments. 
Soon his mind conceived the idea of using the inven- 
tion for transmitting intelligence over a distance. 
He endeavored to send a message without wires over 
miles where Hertz used yards. Instead of the wire 
hoop, Marconi devised and used a more sensitive ap- 
paratus. He found that an instrument called the 
coherer was enormously sensitive to the new electric 
waves, and he soon was transmitting signals for 
many hundreds of yards on the estate of his father 
in Italy. By diligent labor he increased this dis- 
tance, and shortly was telegraphing without wires 
across the English channel, and not many years 
later, he transmitted the letter "S" in telegraphic 
code across the Atlantic by means of wireless. 

To Marconi, therefore, belongs the honor of 
having perfected the wonderful invention of radio, 
first discovered by Hertz. Radio telephony, con- 



HISTORIC 13 

trary to popular opinion, is not a new invention 
either. It has now been known for over two dec- 
ades. Radio telephony, as we know it today, was 
first invented by Valdemar Poulsen, the Danish 
Edison. Instead of using a crashing spark at his 
sending station, he used a silent electric arc with 
certain adjuncts. This was not only entirely noise- 
less, but it gave rise to something new, viz., Contin- 
uous Waves. Heretofore, radio engineers had al- 
ways used the electric spark which produced inter- 
rupted waves. With these sparks, we could not 
transmit the human voice because the interrupted 
waves would break up the words in such a way 
that nothing intelligible could be heard at the re- 
ceiving station. It is as if you were trying to talk 
and somebody was vibrating the hand to and from 
the mouth rapidly. Naturally, no intelligible 
words can be heard when this is done. Since 
Poulsen's time, radio telephony has been well known 
to the radio fraternity and many messages have been 
sent. Thus for instance, in 1915, words spoken at 
the Eiffel tower station, Paris, were distinctly heard 
in Arlington, which is on the outskirts of Washing- 
ton, D. C. At another time, the human voice flung 
out into space at Arlington, was heard distinctly 
at Honolulu, a distance of over 5000 miles. So 
you see, the art of radio telephony is not of recent 
origin, as people still believe. Not only is it possi- 
ble to send the human voice from one radio trans- 
mitting station to a radio receiving station, but in 



14 RADIO FOR ALL 

1916, an experiment was made whereby people sit- 
ting in the dining room of the Waldorf Astoria 
could hear the sound of the surf of the Pacific Ocean 
at San Francisco, a distance of over 3000 miles. 
This was accomplished by hooking up the radio sta- 
tion to the ordinary land station, while the radio re- 
ceiving station was at Arlington, Va. Then the radio 
waves were conducted along an ordinary telephone 
wire stretched between Washington and New York, 
and the roar of the ocean was heard through the 
ordinary telephone receivers connected to the tele- 
phone switchboard in the Waldorf Astoria. The 
public for many years refused to be interested in 
radio telephony until very recently, when our broad- 
casting stations began to send out regular enter- 
tainment by radio. Then the newspapers began to 
take it up, and today radio is a household word in 
every American home, be it located in the city, the 
suburbs or in the country. 



CHAPTER II 
WAVE ANALOGIES 

FIRST of all it is necessary that you implant 
thoroughly into your mind the fact that there is 
nothing mysterious about radio; it is subject to 
natural laws the same as other phenomena. 




What is a radio wave? It is not any different 
physically than a sound wave or a wave in the ocean. 
If we throw a heavy stone in a still lake, it makes 
what we call a splash. This wave rapidly extends in 
the form of circles, as shown in Fig. 1. The heavier 
the stone and the higher it falls, the greater the 
splash, and the higher the waves. It is exactly so in 

15 



16 RADIO FOR ALL 

radio. If by means of certain electrical apparatus 
connected to an serial, we excite this serial electri- 
cally, waves are set up in the space exactly as water 
waves are set up on the lake. Radio waves, just as 
do the water waves, branch out in all directions. 
With the water waves this is not so true. A true 




Fro. 2. 

water wave, as we know, is carried along only upon 
the surface of the water. A few feet below the water 
and immediately above the water, no water waves 
are had. A more strict analogy would be 
sound waves. Take for instance, a church bell. 
By giving it a blow with a hammer, we excite this 
bell. What happens? Sound waves are set up 
in the air in all directions from the bell. Whether 
you are on the street level, 100 feet below, whether 



WAVE ANALOGIES 



17 



you are 100 feet above in an airplane, whether you 
are in a building where it is on the same level as 
you are in all these positions you will clearly hear 
the ringing of the bell. (Fig. 2.) What does this 
mean? Just this. The sound waves are propagated 
in every direction in 
the form of waves, 
invisible to the 
eye, but "visible" 
to the ear. These 
waves are exactly 
of the same shape 
as are the ocean 
waves or water 
waves with the 
difference that the 
sound waves go 
out in the air in 
the form of 
spheres. In other 
words, the first 
sound wave leav- 
ing the bell F '- 

would be a sort of invisible globe all around it. The 
wave rapidly branches out, becoming larger and 
larger, always remaining, however, in the form of a 
sphere, as seen in Fig. 3. If the sound waves do not 
go out in the form of spheres, it would not be possi- 
ble for us to hear them in all directions as we have 
seen in Fig. 2. We, therefore, come to the conclusion 




18 RADIO FOR ALL 

that sound waves that leave a bell branch out, 
above, below, sideways, in fact in all directions. 
It is exactly so in radio. The serial of the 
broadcasting station, or other radio transmit- 
ting station radiates exactly as does a bell. Both 
are transmitters of waves. The radio waves go 
out in the form of spheres as well, branching out 
in every direction of the compass, as well as below 
and above. Not only do the radio waves pass 
through the air the same as the sound waves, but 
radio waves pass through solid objects also, in an 
easier manner than sound waves. 

We all know that we can hear a bell even if 
windows are closed. In other words, the invisible 
sound waves pass through the window panes al- 
though we cannot see the sound waves. Radio 
waves do exactly the same thing, with the exception 
that they pass through solids far better than do 
sound waves. If we are far down in a basement, and 
providing it is sound proof, we no longer hear the 
bell, but radio waves go through solid stone walls 
with great facility, and are, therefore, not stopped 
by such obstacles. Radio waves even pass through 
mountains, providing these mountains do not con- 
tain ores or other metallic substances. Radio 
waves also pass through the water just as sound 
waves do. We all know that if we suspend a bell 
below water, it may be heard if we sink a tube into 
the water and apply our ear to it. Thus radio 
waves may be received in submarines totally sub- 



WAVE ANALOGIES 19 

merged in water. Radio waves also pass through 
the earth with great facility. As a matter of fact, 
it is possible to receive radio messages readily, as 
we will see in a later chapter, by burying an insu- 
lated wire in the ground. Such a wire, though 
deeply buried, readily intercepts radio messages. 

We therefore have learned here that there is 
nothing mysterious about the radio waves any more 
than sound waves. Both are subject to similar 
natural laws. Not only this, but as we all know 
the farther away we go from a ringing bell, the more 
difficult it is to hear it. The greater the distance 
the less able we are to hear the bell. The reason is 
of course, that the original wave, as we increase the 
distance between ourselves and the bell, becomes 
larger and larger and soon covers a tremendous dis- 
tance. Finally there comes a point where we no 
longer can hear the bell. This may be a distance of a 
mile or less, that is if we have ordinary hearing. 
There are, however, persons and animals whose 
hearing is so acute that they can hear the same 
bell much further by reason of their being 
more sensitive. 

If we were to take two horns and point them in 
the direction of the bell, as shown in Fig. 4, and 
apply the ear pieces to our ears, we would be able 
to hear the bell again, although without these appli- 
ances, we would not be able to hear it at all. Why is 
this so? The reason is that the vibrations that 
reach our ears normally are too weak to be inter- 



20 



RADIO FOR ALL 



cepted by our small ears. By enlarging our ears, 
as shown in Fig. 4, we intercept many more weak 
sound waves, and these waves, all being collected 
into our ears bunched together, so to speak are 
sufficient to again impress the diaphragm in the ear, 




FIG. 4. 



and we are thus again enabled to hear the sound. 
We merely cite this interesting experiment because 
it holds true in radio as well. If we have a 
transmitting station, or a broadcasting station, we 
can hear it only up to a certain distance with a given 
apparatus. If we take a small aerial, which we can 
liken to a normal ear, we can use it only for a given 
distance, let us say 25 miles. If we move this aerial 30 
miles away from the radio broadcasting station, we 
can no longer hear it. The case here is exactly as 
with the sound waves. The radio waves have now to 
cover enormous areas, and there are not enough 



WAVE ANALOGIES 21 

waves, so to speak, to leave any impression upon 
our small serial. If, however, we were to double or 
triple the size of the serial, we would do physically 
the same thing as we were doing when we attached 
the two horns to our ears. By having a larger 
increased serial with more wires, we would, by 
means of this, intercept more waves than we could 
with a small normal serial; consequently with such 
an serial we could hear the broadcasting station 
again, even though we were removed 35 miles from 
it. You see that the analogy between the sound 
wave and the radio wave holds pretty true, all the 
way through. Of course, in radio we have other 
means to bring in the signals even if we are removed 
still greater distances. It would not always be 
practical to make the serial tremendously large in 
order to hear greater distances, also we would not 
expect to hear our bell 20 miles away by means of 
even large horns. We would have to devise some 
other more sensitive means to hear the bell, and 
there are such means at hand today in super- 
sensitive electrical microphones which magnify the 
very weakest sounds. So too in radio it is not 
necessary to build a larger and larger serial, the 
more we remove ourselves from the broadcasting or 
transmitting station. Instead, we use more sensi- 
tive apparatus which will magnify the sounds in an 
electrical manner, so that we can hear the station 
even though we are removed thousands of miles 
from it. 



22 



RADIO FOR ALL 



WAVE LENGTH 

What do we mean by wave length? We often 
hear in radio that a certain station transmits at a 
given wave length, say 360 meters. What does 
this mean? First we might state that a meter is a 
measurement the same as the yard. A meter, 
roughly speaking, measures 40 inches. All Euro- 
pean countries instead of yard, foot and inch use the 







meter, centimeter and millimeter. The meter has 
one hundred centimeters and one thousand milli- 
meters. Let us now return to our stone which we 
dropped into the water. If we were to place our 
eye on a level with the water, and someone was to 
throw a stone into a quiet surface of water, what 
would we see? Fig. 5 shows this. We would see 
a wave coming out, as shown in our illustration. 
Any water wave is composed of two distinct parts, 
the crest and the trough. In other words, the water 
first comes up then dips below the original surface, 
then up again above the original surface, etc. In our 
illustration, we have shown in dotted lines the orig- 



WAVE ANALOGIES 23 

inal surface of the water. The disturbance of the 
stone has caused the water to expand into waves. 
Now then, the wave length is that portion which ex- 
tends from crest to crest. In Fig. 5 we see what a 
wave length consists of. It starts at the top of the 
crest, covers the trough and again up to the crest. 
This is exactly one wave length, because it embraces 
the total make-up of one complete wave. 

By throwing an ordinary stone into the water, 
such a wave length may be anywhere from one foot 
upwards. Out on the ocean where we have very 
large waves, so called swells, such ocean waves may 
reach the length of about 300 yards or 100 meters 
or more. We might, therefore, say that an ocean 
wave has a wave length of 100 meters. 

In radio we have the same sort of waves, and 
these waves go out into space in all directions, as 
we have learned before. In radio we can make a 
wave length from a few yards or a few meters up 
to several thousand meters and over. This all de- 
pends upon the apparatus we use. It would be 
the same with our bell. A very small bell, only a 
few inches high, would give very small sound waves, 
while one of the big church bells would give a much 
bigger sound wave. In radio too we have the same 
thing, and we can change from a short to a long 
wave length. 

What are the different wave lengths used in 
radio? It has been found that short waves do not 
travel over such great distances as long waves do. 



24 RADIO FOR ALL 

Using receiving instruments of an ordinary sensitiv- 
ity, it has been found that it is better to use a wave 
of 2000 meters or more, if we wish to transmit mes- 
sages over several thousand miles, as for instance 
across the ocean. A small wave length does not 
pass as readily over such great distances. 

RADIO TELEGRAPH AND RADIO TELEPHONE WAVES 
How do the waves in radio telegraphy and radio 
telephony differ? In radio telegraphy we simply 
hear the plain wave in our telephone receivers, if 
thus we may term it. If the operator in the trans- 
mitting station presses his key, groups of waves are 
sent out into space as long as the key is depressed. 
At the receiving side we hear the waves making a 
buzzing sound for the length of time that the key is 
depressed at the sending station. If the key is 
pressed down for a second, we .hear a buzz for a se- 
cond. If the key is depressed for two seconds we 
hear the buzz for two seconds, and by means of this 
buzzing sound the telegraphic signals are repro- 
duced^ Usually a code such as the Morse or the 
Continental is used. For instance, a short buzz will 
be the letter "E" while "SOS" would stand for 
the following (a short dash be- 
ing a short buzz, a long dash being a long buzz). 
In radio telephony, however, we have a different 
and more complicated action. In the first place, 
we hear sounds, words, and music exactly as they 
are produced at the broadcasting or transmitting 
station. Two distinct things happen. The aerial 



WAVE ANALOGIES 25 

is made to send out a radio wave that is continuous. 
This wave cannot be heard by the human ear with 
ordinary receiving apparatus. It is what is techni- 
cally called C.W. or Continuous Wave. It is also 
used to carry along the human speech. At this point 
we must resort again to our water wave. Suppose we 




Fw. . 

throw a stone into a river. At the same time that the 
stone is thrown we also throw a cork into the water, 
at the same spot. What happens? The cork is 
carried along by. the current as shown in Fig. 6. 
First we see the cork in position 1 . A little later we 
see it in position 2. Still later in position 4 as 
shown on the dotted lines. The cork, therefore, is 
carried along by the wave as well as by the current. 
As the waves progress, the cork progresses also. 
Exactly the same thing happens when the human 
speech is impressed upon the radio carrier wave. 
By certain means too technical to go into here, the 



26 RADIO FOR ALL 

vibrations made by the voice are carried along upon 
the carrier wave, exactly as the cork is carried upon 
the water wave. At the receiving side we only hear 
the words or music, for the reason that the carrier 
wave is inaudible. Hence, nothing but the words 
or speech are heard by us in our receivers. 

SPEED OF WAVES 

It might not be amiss to say a few words about 
the speed of waves in general. If we drop a stone 
into the water, we all know that the speed at which 
the waves spread out is rather slow a few feet per 
second as a rule is all. Sound waves on the other 
hand travel at the rate of 1,100 feet per second. The 
speed of sound waves we therefore see, is consider- 
ably in excess of that of water waves. 

Radio waves travel with the speed of light, 
namely, the enormous speed of 186,000 miles per 
second. We, therefore, can understand that if a 
message is sent out anywhere on our globe, it will 
be received at any place almost instantaneously; the 
greatest distance that a radio wave or a message 
could travel over would be 12,000 miles, for the rea- 
son that the circumference of the earth is 24,000 
miles. You will see, therefore, that a radio wave 
would travel around the earth at the rate of almost 
eight times in one second, and, although a radio 
message was received over a distance of 12,000 miles, 
it would be received in a small fraction of a second, 
too small to measure. For practical purposes, 
therefore, a radio message sent out from no matter 



WAVE ANALOGIES 27 

what distance on earth may be said to cover the 
distance instantaneously. 

POPULAK MISCONCEPTION AS TO RADIO WAVES 

Many people have an idea that radio waves 
broadcasted by a transmitting or broadcasting sta- 
tion, change their form as they are sent out into 
space. Many people think that, when we speak of a 
360 meter wave length, that this has something to do 
with the distance of the sending station or of the 
distance that the radio waves cover. Nothing 
could be more erroneous. It should be thoroughly 
understood that if the Pittsburgh broadcasting sta- 
tion is sending out a message transmitted on a 360 
meter wave, the length of the wave will remain 360 
meters no matter how far it travels. A ship out 
on the ocean 3000 miles away from Pittsburgh may 
hear the Pittsburgh station ; it will be necessary in 
order to hear it to tune the receiving instruments to 
360 meters, otherwise Pittsburgh cannot be heard. 
Therefore, no matter how far a radio wave travels, 
it does not change its length. This is true of every 
wave no matter what its length, whether 100 
meters or 5,000 meters. The length of the wave 
never changes between the transmitting and the 
receiving stations. 

As we have seen before, the different wave 
lengths are purely arbitrary. For instance, the wave 
length of 360 meters has been chosen only be- 
cause it does not interfere with the radio amateurs 
who transmit on a wave length of 200 meters, and 



28 RADIO FOR ALL 

the ship stations which send out on about 600 meters. 
It stands to reason that if all stations were to send 
at exactly the same wave length, we would get noth- 
ing but a jumble. 

To elucidate: Suppose you have six pianos in 
one room, which are all tuned alike ; if we have six 
players sitting down at the pianos and each hits the 
same key, we will only hear that one note, let us say 
A. You could not possibly detect it if five were 
striking the key A, because all of the players are 
transmitting on the same sound wave length which 
transmits only the note A. Suppose, however, that 
one operator is striking the key A while another 
strikes the key E. We can immediately eliminate 
one or the other, and by a little concentration of 
our ear, we can hear either A or E. In other words 
the two pianos are now transmitting at different 
sound wave lengths, the wave length of E being 
different from the wave length of A, and vice versa. 
We can go still further in the analogy. Suppose 
one person plays a tune on the low treble, while at 
the same time another person in the same room plays 
a different tune on the high treble. With a little 
concentration we can listen to one tune or to the 
other. Of course, if we pay no strict attention we 
will hear both pianos play simultaneously. It is ex- 
actly as if two people talk at the table at the same 
time. You can listen to one and shut off your mind 
from the other speaker as you well know. In other 
words, you are "tuning out" the unwanted speaker. 



WAVE ANALOGIES 29 

It is exactly so in radio, only we have better means 
in radio because we can tune out entirely one sta- 
tion or another by means of tuning appliances so 
that we can hear either one at will. That is the 
reason why different transmitting stations send on 
different wave lengths. It is purely an arbitrary 
arrangement so as not to confuse the various receiv- 
ing stations. 



CHAPTER III 

TRANSMITTING 

(GENERAL) 

We have learned something in the previous chap- 
ter about transmitting. We will now go a little 
further, but must be a little more technical here. 




FIG. 7. 

There are several ways of transmitting by radio; 
the oldest and historical method is shown in Fig. 7. 
Here we have an ordinary spark coil such as is used 
in automobiles, a few dry cells, a key and the so- 
called spark gap which may consist of wire nails 
or better two zinc balls. Every time we press the 
key a spark jumps across the open space in the spark 
gap. By connecting one end of an serial to the 
spark gap and the other end to the ground, which 

30 



TRANSMITTING 



31 



may be a water pipe, or a steam radiator, radio 
waves are sent out into space. This is the original 
arrangement that Marconi used for transmitting 
messages. The serial or antenna used here may be 
of any size or shape. The one which we have shown 
is a simple single wire, which may be 50 or 100 feet 
long. Such a little station as this may be used to 
send a radio message over several miles. A station 
of this sort, however, is very crude because it is un- 
tuned; by this we mean, first, that it sends out 





STRING 



TAUT 

WIRE SOUND BOX 

Fio. 9. 

impure waves. We might compare this to a string 
held between two nails and plucked with the finger, 
when we would hear some sort of noise. In other 
words, it would be an impure wave. We might 
mention, by the way, that an impure wave is one 
that has several notes mixed up with the fundamen- 
tal note that gives rise to a noise rather than to a 
note, see Fig. 8. Now turn to Fig. 9 ; here we have a 
wire stretched very taut between two nails on a 
sound board such as an empty box. By tightening 
the wire we get a pure or clear note similar to that 



32 RADIO FOR ALL 

produced when we pluck a string on a violin or a 
mandolin. We all know that the violinist, before 
beginning to play, has to tune his violin before play- 
ing in order to get a pure note. This is his way 
of tuning up an instrument. Referring back to 
our description of simple radio transmitting, as 
shown in Fig. 7, this sends out what we might term a 
radio noise, but not a pure radio note. Furthermore, 
it is found that if we should take a short metal wire 
and stretch it taut, it would give a very high note. 
Thus, we know that on a harp for instance, the 
highest note will be the short strings and the deep 
bass notes will be the long strings. It is exactly 
so in radio. In other words, a long serial will give 
a long wave length, while a short serial will give 
a short wave length. 

Just exactly as a manufacturer of a piano knows 
what the sound wave length of the longest string of 
his piano is, so the radio engineer will know on 
what wave length a given aerial will send. 

Roughly speaking, an serial 100 feet long will 
give a wave length of about 140 meters, while an 
serial 200 feet long will give a wave length 
of exactly twice the length of the shorter one or 
280 meters. 

Suppose, with our little outfit shown in Fig. 7, 
we wish to send out a wave length of a thousand 
meters; we could do this by making an serial 
833 feet in length. That, however, would not be 
practicable because not in all instances could we 
find that much room for the serial. 



TRANSMITTING 33 

We, therefore, resort to another means, and we 
build an serial indoors which we attach to the orig- 
inal serial, a sort of a sending tuning coil, which 
we show in Fig. 10. This tuning coil is the same 




WATER PIPE GROUND 



Fia. 10. 



wire which we use for the serial, wrapped around a 
frame or tube, as shown in Fig. 10. This coil 
means simply the additional wire which is neces- 
sary to lengthen our serial in order to make it long 
enough to give us our thousand meters. By means 
of the slider, which runs up and down the wire 
convolutions, we now have the means of changing 
the wave length merely by adding more or less wire. 
If this is not entirely plain, take a violin as an ex- 
ample. When the violinist wishes to transmit a 
certain sound wave he plucks his string first without 




34 RADIO FOR ALL 

touching his hand to it. As he presses down 
on the string, he automatically makes it shorter and 
shorter, and the further down his fingers slide, the 
higher and higher the note becomes. He does here 
exactly the same thing as the slider does on our 

sending tuning 
coil, that is, he 
changes his 
sound wave 
length.Fig.il. 
In other 
words, if he 

SHORT SOUND LONG SOUND win+c a Inner 

WAVE WAVE wants a long 

FlG - 1L sound wave he 

slides his finger down the small end of the violin, 
and if he wants a short sound wave, he slides his 
finger towards his chin. This changes the sound 
wave length in exactly the same way as our sending 
coil changes the radio wave length. Both are fun- 
damentally the same. 

When Marconi first rigged up his little sending 
station, as shown in Fig. 7, he naturally could only 
send out radio telegraphic signals. Every time he 
pressed the key, radio waves were sent out. When 
he pressed the key for a second, a buzzing noise was 
heard for a second in the distant receiving tele- 
phone receivers. If he pressed the key for two 
seconds, a buzzing sound for two seconds was heard. 
By this means the telegraphic code is made up, as 
shown in Fig. 12. At the present time, the Conti- 
nental code is used almost exclusively, and today, 



TRANSMITTING 

WIRELESS CODES 



35 



LETTERS 



MORSE 



CONTINENTAL. 



EE 



f^ 




SSV 



5S 



Si 



B 





SSK 



tt4* 



a- 1 ;? 




^^ 
'""> 

y /*: > 



:L:I. 



arr.'i*. 







ABBREVIATED NUMERALS U5ED BY CONTINENTAL OPERATORS 
t mm aoiHB5e*BHi -4 5 e 
ean T *a 8 9MB* to MB 

-WIRELESS ABBREVIATIONS* 
G.E.-GOOD EVENING 4--PLEASE START ME,WHEPE 
0.N. NIGHT 3O-NO MORE 

GM. MORNING TS'BEST REGAfeDS 
G.A. GO AHEAD 
D.H. FREE MESSAGE 
MSG-MESSAGE. 
O PR. -OPERATOR 

-DISTRESS SIGNALiS- 
S.O.S. <=>* < 

FIG. 12. 



36 RADIO FOR ALL 

as in Marconi's time, when the operator at his send- 
ing outfit presses down his key for a short duration, 
this is interpreted as a dot at the receiving side, and 
when he presses his key down for a longer period 
this becomes a dash on the other end. By means of 
dots and dashes, the telegraphic code is made up. 

It is not the easiest thing to learn this code; it 
requires practice, the same as playing a piano or 
operating a typewriter. It must be learned, and it is 
just as important to learn to send as to receive. 
Of course, as soon as we have mastered sending, it 
is simple to receive, although, as we might suspect 
every operator has his individual characteristic. For 
instance, some of the operators, particularly the 
good ones, will space the dots and dashes in a certain 
clear manner, while others will run the signals to- 
gether, making it very difficult for the operator at 
the receiving end to get the correct message. Some 
operators will go very fast, while others will go 
slowly. Soon it becomes possible for operators to 
recognize each other simply by their "hand." In 
radio telegraphy each sending operator has a 
sort of telegraphic "voice" easily recognizable by 
his friend. 

In Fig. 7, we showed a simple sender. Of course, 
it goes without saying that soon after Marconi 
started his experiments, more complicated sending 
apparatus was designed. It was found, for in- 
stance, that the spark sent out by such a station was 
received at the other end very mushy and not at all 



TRANSMITTING 37 

clear. It was nothing but a noise. Soon new 
apparatus was invented, such as, for instance, a 
quenched spark gap which clarified the sound to 
such an extent that instead of hearing a mushy, 
noisy spark at the other end, a clear whistle or flute- 
like sound was received. It was found that such a 
spark carried much further and could be worked 
readily through static, which is the bane of the radio 




FIG. IS. 

telegrapher. Static, by the way, as we will see later 
is an atmospheric, electrical disturbance in the air 
which makes receiving very difficult at times. 

There are now many different transmitters in 
use, as for instance, the electric arc which may be 
used for transmitting. This has the advantage of 
giving rise to what is called continuous waves ; this 
is made clear by the diagram shown in Fig. 13. 
When we press the key of the old Marconi outfit, 
we send out into space radio waves which have some- 
what the form shown in Fig. 13. These waves start 
with a high pitch, as we might say, and die out rapid- 
ly. This happens a great many thousand times 
each second, but these waves are not continuous. 
They are small wavelets, as we might term them, 
which are disrupted and do not form a continuous 
line. Look at Fig. 14; this is what we might term 
a continuous wave, and is a wave which is sent out 



38 



RADIO FOR ALL 



by an arc transmitter and by a vacuum tube trans- 
mitter such as is now used universally at broadcast- 
ing stations. As long as the arc from the sending 
set is transmitting, a continuous wave is sent out 
into space which does not vary. It does not take 
a technical mind to know that the waves sent out, as 



FIG. 14. 

shown in Fig. 14, must be better and clearer than 
the interrupted waves sent out in Fig. 13. As a 
matter of fact, the interrupted wave or the wave 
made by the spark is coming into less and less use 
as time goes by. This is the day of the Continuous 
Wave commonly called C. W. It is the Continuous 
Wave that makes radio telephony possible. 




FIG. 15. 

Let us make a comparison again, which can be 
easily understood, and which may serve to make the 
interrupted wave and the Continuous Wave clear 
in our minds. Take a number of pipes as shown 
in Fig. 15 ; one person stands at one end and another 



TRANSMITTING 39 

at the other end. One talks into this interrupted 
pipe, which may be 100 feet long, and as will be read- 
ily seen the person at the other end will have a great 
disadvantage in hearing the speaker because the 
pipe, being interrupted so many times, breaks up 
the speech. This is the analogy for spark waves. 
Now turn to Fig. 16; here we have a long pipe, 
the same as we use in our speaking tubes, which is 
free from interruptions, and is continuous all the 
way through. You can readily understand why the 
person at the other end will have no trouble in hear- 




.Fio. 10. 

ing what the speaker says, for the reason that the 
pipe is continuous all the way through. This contin- 
uous long pipe stands for a continuous wave. This 
of course, is not a strict analogy, but may serve to 
implant in the reader's mind the difference between 
an interrupted spark wave and a continuous wave. 

POWER IN SENDING 

So far, we have only considered transmitting 
generally. The question is often asked, how much 
power do we need to transmit to a given distance? 
This is an entirely erroneous conception for a very 



40 RADIO FOR ALL 

simple reason. The power used in sending has 
fundamentally nothing to do with the distance. For 
instance, it was demonstrated, as we stated else- 
where, that a number of American amateur send- 
ing stations were heard clearly in England, although 
they had a power of only 1 kilowatt, which is 1000 
watts. This power is equivalent to burning twenty 
50-candle power incandescent Mazda lamps on a 110 
volt lighting current. Certainly a very moderate 
amount of power. On the other hand, the commer- 
cial companies as a rule use a power which is at 
least 50 times as great and often 100 to 300 times 
as great. Why is this so? A few words will ex- 
plain. When our receiving apparatus was very 
crude, and not at all sensitive, a one-inch spark coil 
could not transmit more, than one mile. In other 
words, it could not be heard further than one mile 
with ease in the time of the coherer, an instrument 
of which we will speak later on. A few years later, 
when detectors which were much more sensitive than 
the coherer, came into vogue, the same one-inch 
spark coil could be heard for 10 miles. Today, by 
means of our super-sensitive vacuum tubes, it is 
possible to hear a one-inch spark coil perhaps a 
hundred miles and over. So you see the power 
that we use at the transmitter has no bearing on the 
distance. As a matter of fact, it can be proved 
theoretically that a one-inch spark coil connected 
to six dry cells, and providing we have a sufficiently 
large serial, may be heard as far as it is possible to 



TRANSMITTING 41 

go on this globe, which is 12,000 miles. As receiv- 
ing instruments are becoming more and more re- 
fined, this stage will be reached some day, because 
the waves of this small one-inch coil certainly reach 
that distance. The transmitting distance is simply 
a matter of the sensitivity for the receiving station. 
That this is not theory, is best proven by the fact 
that our sending stations are becoming less and less 
powerful. Years ago they were great thunder fac- 
tories where a tremendous amount of power was 
used. This is a thing of the past. While we still have 
powerful commercial stations, their power is shrink- 
ing as the years roll on. A time will come when 
only an insignificant amount of power will be used 
to fling messages around the globe. 



CHAPTER IV 

RECEIVING 

GENERAL 

THE radio receiving station is for the sole pur- 
pose of receiving radio intelligence, be it radio teleg- 
raphy in code or radio telephony in speech, music 
or other entertainment. 

It should be understood at once, before going 
further, that no matter what receiving station you 
have, it can receive either radio telegraphy or radio 
telephony. The receiving station has the exact 
counterpart in your ear. It receives any and all 
sounds and noises that are floating about in the air. 
So it is with the radio receiving station; with it you 
can hear, if properly adjusted, any and all distur- 
bances that are flung out into space by the various 
transmitting stations. Of course, the radio receiv- 
ing station has limitations, just the same as the hu- 
man ear. To make this plain, there are many noises 
and sounds that the ear cannot hear, due to its 
physical limitations. For instance, sounds below 
16 vibrations per second cannot be detected by the 
ear. Certain animals, however, can hear these 
sounds, as their hearing apparatus is tuned to low 
vibrations. Going up on the scale we find that the 
ear no longer responds when the vibrations go above 
30,000 per second. Certain birds and insects, 
however, can hear such sounds perfectly, their 

42 



Photograph by Pacific & Atlantic Photos, 



President Harding delivering his address at the Arlington Cemetery on Decoration 
Day. His voice was picked up by the microphones seen in front of the pulpit and 



itted by radio. 




Photograph by Keystone View Co., 
Here we see the huge amplifiers which were used to 
receive President Harding's speech. The voice issues 
with tremendous volume from these horns and can be 
heard within 500 to 1,000 feet from the tower. 



RECEIVING 43 

ears being attuned or adjusted to these vibra- 
tions. The same is the case in radio ; certain waves 
may be heard in a receiver while certain others may 
not. When we said, therefore, that a radio receiver 
can receive all messages that are floating about, we 
have said so only with certain restrictions. The 
radio receiver, which is just like a human ear, can 
only record certain radio impulses, others cannot 
record at all unless we take recourse to artificial 
means, as we will learn later on. As explained in 
previous chapters, receiving instruments are becom- 
ing more and more sensitive for which reason we can 
hear the sending station further and further away. 
If we have a broadcasting station which is sending 
out a band concert, and if we were to use Marconi's 
first instrument, the coherer for receiving purposes, 
it would not be possible for us to receive this con- 
cert at all because Marconi's coherer is totally 
unsuited to receive broadcasted radio music. After 
Marconi's coherer came the auto coherer, a some- 
what more sensitive instrument. With such an in- 
strument a broadcasting station could possibly be 
heard five to ten miles, but no further. Next came 
the crystal detectors ; with a good one we may hear 
the broadcasting station at a distance of 25 miles 
or more. Still later came the audion or vacuum 
tube. This instrument, being enormously more 
sensitive than a crystal detector, at once increased 
the range up to a thousand miles and over. Thus, 
for instance, the station WJZ at Newark N". J., was 



44 RADIO FOR ALL 

clearly heard by receiving stations 1400 miles away. 
Of course, the waves of the broadcasting station, as 
we have mentioned before, go much further, only 
we no longer hear them even with our present va- 
cuum tube detectors. But the time is surely com- 
ing when, by means of a good detecting instrument, 
not as yet invented, we will be able to hear WJZ 
all over the globe. We may state right here that the 
range of the receiving station is mostly dependent 
upon the detecting instrument, all other things be- 
ing equal. The range of a receiving outfit, there- 
fore, depends entirely upon the sensitivity of the 
detecting means. 

We often hear the remark made that Mr. John 
Smith has a "high power" receiving station. This 
is a lay expression which is totally wrong. There 
is no such thing as a "high power" receiving station. 
The statement should be that John Smith has an 
extraordinarily sensitive receiving station. 

If you have any trouble in grasping these points, 
let us take recourse to another analogy. Using 
a candle, which will be our transmitting station, our 
eye will be the sensitive receiving station, a few feet 
away. We can see the candle perfectly, as well 
as the flame. Place the candle 500 feet away and 
we are not aware of its presence, we just 
see the flame rather indistinctly. At 1,000 feet, the 
flame plus the candle has shrunk to a fine luminous 
point, if we are in total darkness. Remove the 
candle 10 miles from our eye and we no longer see 



RECEIVING 45 

either the candle or the flame, although we know 
perfectly well that the candle is still burning and 
is sending out its light rays. 

The trouble is not, therefore, with the sending 
station, which is our candle in this instance, but 
with our eye. In other words, our eye is no longer 
a sensitive receiving detector for the light waves, al- 
though we know perfectly well that the light rays 
are still there. How can we prove this? By very 
simple means. We attach an amplifier to our eye, 
this being a telescope. If we focus this telescope 
correctly upon the candle, and look through 
our amplifier telescope, we again will not only see 
the distant flame of the candle, but if the telescope 
is a good one we will see the candle as well. Astron- 
omers are making use of this very thing every day. 
Millions of stars cannot be seen by the naked eye, 
but the telescope brings them closer by amplifying 
the stars to such an extent that they become visible 
to our eye again. But the astronomer goes still 
further. He knows that the eye itself is not a very 
sensitive detector for light. He, therefore, substi- 
tutes a photographic plate for the eye. By expos- 
ing the photographic plate to the light of a star 
for many hours at a time, the star is thus photo- 
graphed upon the plate, which star was previously 
totally invisible to the eye with the best tele- 
scope. In other words we have here to do with 
a super-amplifier. 

We make use of just such artifices in radio as 



46 RADIO FOR ALL 

well. For instance, a single vacuum tube is only 
able to detect radio signals for a given distance. 
By adding more vacuum tubes, more "stages" as we 
call them in radio parlance, we step up the faint sig- 
nals until finally a radio signal that could not be 
heard at all with a pair of telephone receivers, and 
a crystal detector, will roar out of the amplifying 
horn with ear-splitting strength. We have done 
in radio exactly the same thing as the astronomer 
has done with his telescope. We have amplified 
the radio waves while the astronomer has amplified 
the light waves. Both phenomena are exactly alike 
in theory as well as in practice. The analogy holds 
good much further. If the astronomer has a de- 
fective telescope in which the lenses are cracked or 
covered by fog or moisture, we know in advance that 
he will not see well. His amplification of the dis- 
tant star or planet will be poor or he will see nothing 
at all. It is exactly so with the radio receiving sta- 
tion. If conditions are not right, for instance, if our 
insulation isbad,or if the adjustments of the appara- 
tus are not correct, we will hear the signals faintly, 
and often not at all. Receiving radio waves, there- 
fore, is not any different from receiving light waves. 
If you go to the opera you would not think of using 
the opera glass unless it was properly adjusted 
tuned to your particular eye. You also would 
not have the lenses covered with finger marks. You 
know in advance that you would not see much of the 
opera if you were to do that. The same thing 



RECEIVING 47 

holds true of your receiving set. We must have 
perfect insulation; all metal parts that carry the 
current must make good contact all parts must be 
perfectly adjusted. Only in this case will the re- 
ceiving be 100 per cent., or rather approaching it, 
because we have not as yet reached the stage where 
we can receive 100 per cent. 

We have mentioned before that radio waves pass 
as readily through a stone wall as through the air. 
It, therefore, does not surprise us that we can have 
a modern receiving station in our library with- 
out an outdoor serial at all and the waves will be 
received just as well as if the outfit was stationed 
on top of the roof or out in the yard. This is 
true only if the detecting apparatus of the re- 
ceiving outfit is very sensitive, otherwise we will 
not be able to detect the waves, although they 
are there. 

As a general thing, it has been found in receiv- 
ing that the higher up our receiving apparatus or 
aerial is, the better we can receive. It also has been 
found that one can receive further with a given 
receiver over water than over land. Roughly 
speaking, one can hear twice as well over water as 
over land. To illustrate this, if we had a receiving 
station anywhere near the coast, we should, with 
a good crystal detector, hear a broadcasting station 
25 miles inland. On the other hand, we would hear 
it about 50 miles out on the sea. Scientists are not at 
all certain as to the reason for this, so we will not 



48 RADIO FOR ALL 

dwell upon it here. Furthermore, if in a mountain- 
ous country, particularly where mountains are ore- 
bearing, or if we are at the bottom of a valley, 
our receiving range will be cut down quite 
a good deal. Such mountains make a sort of 
barrier, as they do not pass the radio waves readily. 
Thus, if we are in the midst of a large forest, and 
our serial does not extend much beyond the tree 
tops, we will often have difficulty in receiving. For- 
ests cut down receiving considerably. It should be 
understood that these statements are only general. 
If we have a highly super-sensitive apparatus, we 
can hear in a valley or a forest, although the signals 
will not come in as strong as if we were out on a 
plain. Steel buildings also tend to cut down the 
receiving range. Thus, for instance, if a receiving 
station of moderate sensitivity is located in the 
heart of the New York downtown district, we will 
hear practically nothing from the neighboring 
broadcasting stations, unless of course the aerial ex- 
tends far up above the buildings. All these facts 
should be borne in mind when erecting a good re- 
ceiving station. 

Another point to be remembered is that reception 
during the night time as a rule is better than during 
the day. The reason for this is that during the day 
time the sun's rays ionize the air, which means that 
the sunlight makes the air partly conductive. That 
cuts down the receiving range as well. It is not a 
rare occurance that distant stations are heard twice 



RECEIVING 49 

as far during the night time as during the day. 
Even now commercial stations handle most of their 
traffic between sunset and sunrise because the re- 
ceived signals are much more powerful during 
this time. 

STATIC 

A few words as to this greatest nuisance that 
the radio man has to contend with. Static disturb- 
ance is nothing but atmospheric electricity. We 
are not bothered much with static in the winter time, 
but during the months of May, June, July, August 
and September, there is plenty of it, particularly if 
we have an serial extending up into the air. Static 
makes itself heard in our receivers in a sort of irreg- 
ular noise that cannot be controlled today. Very 
often we hear sharp clicks in our receivers which 
vary up to a loud roar, particularly when a thunder 
storm is approaching. Sometimes the air, even on 
a perfectly clear day, is so highly charged with elec- 
tricity that if we bring the lead-in from our serial, 
close to the ground wire, small sparks will jump 
from the serial to the ground, proving conclusively 
that static electricity is collecting upon the serial. 
These static noises so far have not been corrected, as 
no way has been found to weed out or entirely tune 
out these disturbances. Sooner or later, however, 
some genius will invent a perfect static armihilator. 
When he does that, his future wealth will be assured. 
If you doubt that it is atmospheric electricity that 
causes the racket in your receivers on a nice warm 



50 RADIO FOR ALL 

summer's day, you may manufacture your own 
static when the air is particularly quiet by means of 
your house cat. All you need to do is to stroke the 
fur of "tabby," and let the fur come in contact with 
the bare lead-in of your serial while you have the 
receivers on your ears. You will hear exactly the 
same sort of static noises if you stroke the cat the 
right way, as her fur will generate static electricity. 



CHAPTER V 
RECEIVING INSTRUMENTS 

THE earliest and perhaps the first instrument 
for detecting radio waves was the coherer. This 
was a rather complicated little instrument, and one 
that was difficult to keep adjusted. Furthermore, 
it was not at all sensitive, compared with the detect- 
ing instruments of today. Fig. 17 shows the in- 



Side tube 
for exhaustion-- 



Gloss tube, exhausted 




Silver bevelled 
plugs. 



"Silver-nicKel filings- 



strument which was composed of nothing more than 
two metal plugs surrounded by a glass tube; the 
small space, about one-eighth of an inch, that sepa- 
rated the two plugs was taken up by nickel and 
silver filings. The proportion was roughly, 90 per 
cent, nickel and 10 per cent, silver. The peculiar- 
ity of this instrument was that when radio waves 
struck it, the filings became more conductive, and, 

51 



RADIO FOR ALL 



therefore, passed the electrical current through bet- 
ter. Further, it was possible to ring a bell with the 
coherer. The simplest connection is shown in Fig. 
18. Here we see the coherer attached to the asrial 
and the ground, also a relay, a battery and a bell. 




"Vycelis 



Ground 



FIG. 18. 



The instant that a radio wave impinged upon the 
eerial, the bell would ring, and would continue to 
ring even though the wave had passed. 

In the early days, Marconi provided a sort of 
tapping arrangement which, hitting the coherer, 
disturbed the filings, destroying the conductibility, 
and the coherer was then ready to receive an addi- 
tional signal. This instrument, however, was not 
very satisfactory, because it did not always respond 
to radio waves, and sometimes it responded to 



RECEIVING INSTRUMENTS 53 

static electricity (atmospheric disturbances) as well. 
This instrument, therefore, was soon discarded. 

A somewhat better and simpler instrument is 
shown in Fig. 19. Here are two blocks of carbon 
filed to a sharp edge. On top of the carbon rests 
a sewing or darning needle; the idea is that the 



Steel needle 
Carbon btock UST ll .Carbon block 




Binding posts 



needle makes a slight contact with the carbon blocks. 
This was the first real detector, because unlike the 
Marconi coherer, it was self-restoring, that is, it 
needed no tapping to make it ready for the next 
wave. In other words, dots and dashes could be 
received with this detector with but little trouble. 
The connection is shown in the diagram, Fig. 19 A, 
and it will be noted that a battery is required with 
this detector, although if adjusted exceedingly well, 
such an instrument works without a battery, but 
not so readily. Such a detector is quite unsatisfac- 
tory for the reason that the slightest vibration, such 
as footsteps in the room, disturbs the needle and 



54 



RADIO FOR ALL 



makes the device inoperative until it is adjusted 
again. This was one of its great draw-backs. 

Soon afterwards there was developed the so- 
called electrolytic detector shown in Fig. 20. It 
may be considered, even today, a good detector, and 
while not as sensitive as the best crystal detector 
(this will be discussed later) it has the one great 
advantage in that it "stays put" and does not very 
easily get out of order. The electrolytic detector 




has a fine platinum wire, as shown in the illustra- 
tion that dips into a small cup containing a solution 
of nitric acid in the proportion of about five parts 
of water and one part of nitric acid. We can also use 
a similar proportion of water and sulphuric acid; 
both work very well. The wire which touches the 
nitric acid is exceedingly fine, for which reason it 
is difficult for the eye to perceive it. It is called 
Wollaston wire, and is a fine platinum wire covered 
with a heavy coating of silver. 



RECEIVING INSTRUMENTS 



55 



When the wire is immersed in the acid, the silver 
coating is eaten away by the acid and a fine plat- 



Adjusting screw 



Wollgston 
wire 




Carbon cup to hold acid 



inum wire remains. This wire is less than three ten 
thousandths of an inch thick, so fine that it can 



WollosTon 
wire 




Silver 
coating 



Nitric acid 



hardly be seen. Usually some sort of regulating 
mechanism is used to make this wire dip more or 



56 RADIO FOR ALL 

less into the acid. As a matter of fact, the best 
results are had with the Wollaston wire when it 
barely touches the liquid, as is shown in Fig 21. 
The wire being so extremely thin it curls over 
slightly when touching the acid solution. It will 
be noted that with this style of detector, as shown 




FIG. 22. 



in the diagram, Fig. 22, a potentiometer is 
used. This potentiometer is nothing but a sort of 
resistance, and is employed solely to cut down the 
current from the batteries. High resistance tele- 
phone receivers having a resistance of 2,000 or 3,000 
ohms are used with the electrolytic detector with 
good results. The potentiometer is adjusted until 
the "boiling" noise is reduced to a minimum in the 
telephone receivers, and the detector is now ready 
to receive the signals. With the electrolytic detec- 



RECEIVING INSTRUMENTS 57 

tor, signals have been received over very long 
distances. 

The author was about the first one to introduce 
the use of a carbon cup in connection with the elec- 
trolytic detector, shown in Fig. 20 ; this carbon cup, 
being a conductor, made a much better instrument 
because metal cannot be used. Before the author's 
experiments, small glass vessels having a platinum 
wire fused into them were used, but these were 
rather expensive. The author also found that if a 
small drop of petroleum or paraffin oil was poured 
upon the acid, it would keep the latter from evapo- 
rating. This is quite important, as before this im- 
provement was made, it was necessary to replenish 
the acid almost every day. The author who had 
experimented a great deal with electrolytic detec- 
tors, endeavored to develop such a detector in which 
no loose acids were to be used. A detector termed 
the "Radioson" was designed by him, and this had 
all the elements of the standard electrolytic detector. 
The fine Wollaston wire was fused in a glass tube 
which was immersed in the acid as shown in the 
illustration, Fig. 23. The Radioson was also used 
in connection with the potentiometer and high resist- 
ance receivers just as was the original electrolytic 
detector. Unfortunately the Radioson, once sub- 
jected to strong signals or even too strong static 
currents, would burn out the exceedingly fine Wol- 
laston wire, after which the instrument became 
inoperative. Although the Radioson was perhaps 



58 



RADIO FOR ALL 



one of the best electrolytic detectors ever designed, 
no means could be found to keep it from burning 
out and the manufacture of it was given up by 
the makers. 

Soon after the invention of the electrolytic 
detector, crystal detectors came into vogue. 
Dunwoody was perhaps the first man to use such a 



Electrolyte 




Wollaston wire sealed 
in gloss tube. 



Fra. 23. 

crystal, viz., carborundum. The carborundum crys- 
tal is a green-bottle colored sharp crystal, which 
is a manufactured product. Carborundum is used 
mainly as an abrasive, being harder than glass, which 
it scratches easily. The carborundum detector is 
shown in Pig. 24. The connection is similar to 
that of the electrolytic detector and is, therefore, 
not shown here. As will be seen the carborundum 
crystal is clamped between steel needles under a 
certain amount of pressure, in such a way that the 
needles rest against the surface of the crystal. The 



RECEIVING INSTRUMENTS 



59 



amount of pressure that the needles bear against 
the crystal is determined by experiment until the 
signals come in loudest. The amount of pressure 
varies for every crystal, and must be found by trial. 
Once adjusted, the carborundum detector needs no 
attention, and it will not get out of order readily. 
Jars do not affect it, and for that reason it has been 



Carborundum 




Steel needles 



FIG. ti. 



used to a great extent on board ships, in portable 
outfits, etc. Unfortunately, this detector is not 
very sensitive. As a matter of fact, it is not as 
sensitive as the electrolytic detector, but where sta- 
bility is required this detector is excellent. 

Fig. 25 shows one of the best of the early detec- 
tors, viz., the silicon detector. Silicon is a manu- 
factured substance, which is a by-product of the 
electric oven in the manufacture of abrasives ; it is 
a cousin to carborundum. Silicon is a hard rock- 
like substance of a dark silver-gray color. The de- 
tector is shown complete in Fig. 25. A small piece 



60 RADIO FOR ALL 

of silicon broken from a larger piece by means of a 
hammer or in a vice, about a /4 inch by *4 inch, 
is first imbedded into a soft solder, as shown 
in the separate illustration of Fig. 25. The idea of 
this pellet is that contact is made on five sides with 
the metal, which is simply cast around the silicon, 
and the crystal part of this round pellet is after- 



Blunt brass point 





wards placed in contact with the contact mem- 
ber, as shown in the illustration. The contact mem- 
ber is nothing but a piece of brass, which is not very 
sharp at the end, but rather blunt. The amount 
of pressure upon the pellet is varied by a spring. 
In detectors of this kind, not every point of the 
silicon is equally sensitive. Some points are very 
sensitive while others are not. Some of the sensi- 
tive points require more pressure than others. All 
tnis is found out by experiments. The silicon de- 
tector is quite sensitive, and probably is as good a 
detector as the electrolytic type, with the great 



RECEIVING INSTRUMENTS 61 

advantage that it requires no battery. This was 
the first detector invented that required no battery 
whatsoever to detect radio signals, and for that rea- 
son it is a favorite instrument with the experimenter. 
The silicon detector has also the great advantage 
in that it is not easily "knocked out," as most other 
detectors are. It is not so sensitive to static elec- 




Aerial y 
Detector 



\7 



Phones 



tricity and does not burn out easily. When con- 
nected, as in Fig. 26, a set of receivers of at least 
1,000 ohms should be used for best results. We 
might state here that a 75-ohm receiver, such as is 
used in house phones, should never be used in con- 
nection with radio waves. The results are very poor. 
For short distances a 75-ohm receiver may be 
used, but even then it is not sensitive and not 
very satisfactory. 

Soon after the silicon detector was invented, 



62 RADIO FOR ALL 

Greenleaf W. Pickard, the inventor of the silicon 
detector, invented a host of other detectors, all of 
which use a native mineral crystal, such as, for in- 
stance, iron pyrite, copper pyrite, bornite, etc. All 
of these detectors are used similarly to the silicon 
detector, the crystal being cast into a soft metal in 
pellet form. This pellet is used in the same way as 



Gold wire 



Rodiocite 
crystal 




the silicon detector; sometimes a sharp brass con- 
tact point is used with some minerals and at other 
times a fine wire is used, which latter is termed a 
Cattvhisker. Such a detector is shown in Fig. 27. 
This detector uses as a sensitive member the mineral 
or crystal known in the trade as Radiocite. Radio- 
cite is a treated iron pyrite and is as shiny as polished 
gold. A good piece of radiocite is equally sensitive 
over its entire surface. It is probably as sensitive 
as any of the mineral detectors in use today. As 
with all other crystal detectors, no battery is used 



RECEIVING INSTRUMENTS 63 

in connection with it. In the radiocite detector no 
sharp point is used, but rather a fine gold wire cat- 
whisker. A catwhisker is a piece of fine wire about 
No. 26 or No. 28 B & S gauge phosphor bronze. This 
is attached as a rule to some sort of handle or other 
adjusting means so that the pressure of the wire 
upon the surface of the mineral may be varied. If 
one spot burns out or becomes inoperative, a new 
point is found by experiment. 

One of the most sensitive and most widely used 
detectors is made of Galena, a lead ore of which 
there are different grades. It is known under many 
trade names as well. A good piece of galena is 
probably as sensitive as any crystal yet discovered, 
but it is not stable. A catwhisker, as explained 
under the radiocite detector, is used with the galena 
crystal and the amount of pressure has to be found 
by experiment. Ordinary galena is not sensitive 
on every spot, but there are certain grades which 
are equally sensitive over the entire surface; this 
is known as Argentiferous Galena, which means 
that it is silver bearing. On the other hand not all 
argentiferous galena is equally sensitive, and there 
is no hard and fast rule about it. It must be found 
by experiment. The connection for the radiocite, as 
well as galena detector, Fig. 28, is the same as shown 
in Fig. 26. No battery is used with galena, and as 
a matter of fact a battery will destroy the usefulness 
of it by burning out the sensitive points. With 
galena, a fine brass wire No. 24 or No. 26 B & S 



64 



RADIO FOR ALL 



gauge is used ; a stiff gold wire of the same dimen- 
sion may also be used, as it is non-oxidizing. It may 
be stated here that most any metal wire can be used ; 
they all work equally well with the possible excep- 
tion of iron, which soon becomes coated with rust 
and will then no longer operate. 



Cot-whisKer 
\ 




Crystal-^ 



Binding post 



Binding post 



All crystals are only sensitive if absolutely clean, 
and their usefulness becomes destroyed immediately 
upon being handled with the bare fingers. The 
natural oil of the hands tends to destroy the sensi- 
tiveness as the crystal surface becomes coated with 
it. The best method to employ with all crystals 
is to clean them frequently with a piece of absorb- 
ent cotton moistened with carbon tetrachloride. 
This high-sounding name is nothing but Carbona, 
which may be purchased anywhere. There are 
some liquids advertised under high-sounding names, 
all of which are in reality Carbona; this does the 



RECEIVING INSTRUMENTS 



65 



work 100 per cent, well, and should always be used 
where crystals are employed. After rubbing the 
crystal with the moistened cotton, it should be left 



Double 
binding post 

t_ Cot-whisKer 




Crystal in 
metal cup 



Cat-whisKer 



Crystal 




Flat head 
machine screws 



Spring clip 
Safety pin 




Crystal 




Brass post 
Brass or copper 



for a few minutes until the liquid has evaporated. 
The crystal will then be found in first class 
condition. 

Although we have stated a little further back 
that most crystal detectors have the sensitive mineral 
embedded in a metal pellet, the amateur or experi- 



66 RADIO FOR ALL 

menter does not always require this, and Fig. 29 
shows several simple home-made detectors. The 
illustrations are so self-explanatory, that no further 
details need be given. Base boards may be of wood, 
hard rubber or any good insulator. As will be seen 
in these illustrations, the detector mineral is clamped 
by simple holding devices; anything that will hold 
the crystal down so that it will not move, and at the 
same time make good contact with it, may be used. 
The catwhisker wire is best (a No. 24 or No. 26 
B & S brass gauge), or phosphor bronze wire. It 
may be straight, or coiled in pig-tail fashion, either 
will work equally well. The clever experimenter 
can change the design to suit his own individual 
tastes, and the chances are that the device will work 
well. The trouble with most mineral detectors is 
that their adjustment does not keep for any length 
of time. Jars, or static surges in the serial will 
cause the detector to become inoperative, after which 
it must again be adjusted. The better the crystal 
and the more sensitive spots it has over the entire 
surface, the easier the adjustment will be. 

We now come to a vastly different sort of de- 
tector, namely the Audion, or as it is commonly 
called, the "Vacuum Tube." This detector works 
upon an entirely different principle from any of the 
former ones described, and is in general use today 
for reasons which we shall learn presently. The 
audion makes use of a principle first discovered by 
Edison, and for that reason termed the "Edison 



RECEIVING INSTRUMENTS 



67 



Effect." Edison found that if he placed two fila- 
ments in an ordinary electric lamp instead of one 
filament, and lit them both, a current would flow 
across the vacuum or empty space. It is this prin- 
ciple that is now being used in the vacuum tube. 
Fig. 30 shows a standard vacuum tube where we 
have the filament, which is the same as that used 




X Tube with 
\ plate re- 
J moved. 



Complete 
tube 




Plate 



FIG. 80. 

in an incandescent lamp; this is heated by means 
of a battery of from four to six volts. We next 
have the grid which may be in the form of a grid- 
iron or a spiral, it making little difference which. 
Opposite the filament and with the grid in the mid- 
dle, we find the plate, usually a small piece of nickel 
or other metal. The connection of the simplest 
audion is shown in Fig. 31. If we make the plate 
positive with respect to the filament, we find that 
highly charged electrical particles called "electrons" 



68 



RADIO FOR ALL 



travel constantly from the filament to the cold plate. 
It was soon found that the vacuum tube acted as a 
sort of valve for the electrical current, allowing 
the high frequency currents as they came over the 
serial to travel in one direction in a vacuum, tube 




but not in the other. In this respect the vacuum 
tube is the same as a crystal detector, which also 
acts as a valve, permitting currents to pass one 
way only. 

The vacuum tube was first invented by Dr. 
Fleming, to whom belongs the honor of using it 
first as a detector for radio. He was using only 
a two-element tube, viz., an exhausted bulb contain- 
ing a filament and a plate. Dr. De Forest 
conceived the idea of introducing a third elec- 
trode into the tube, as explained above. The 
purpose of this electrode which he called the grid, 
serves only to control the flow of the electrons at- 



RECEIVING INSTRUMENTS 69 

tracted by the cold plate. It is the grid that makes 
the vacuum tube the exceedingly sensitive apparatus 
that it is. Making the grid alternately positive and 
then negative varies the amount of current that 
flows from the hot filament to the plate, decreasing, 
and even stopping it entirely. The grid simply acts 
as a gate valve which controls the plate current. 
The curious thing about the grid is that it uses no 
great amount of power. A modern vacuum tube 
is exhausted to a very high degree, because it was 
found that unless the vacuum was perfect, the sensi- 
tivity of the tube was very poor. It is not neces- 
sary here to go into a very technical discussion of 
the vacuum tube, as we are merely interested in its 
functioning. The study of the vacuum tube, how- 
ever, is a science in itself today, and for that reason 
it can only be treated generally here. We must, 
however, add that the vacuum tube is far more sen- 
sitive than other detectors, particularly when used 
in connection with other vacuum tubes. It was 
found, for instance, that this was the case when 
several tubes were coupled together; this gives us 
the so-called two-step or three-step amplifier, which 
will be discussed later on. The idea of these ampli- 
fiers is for each to step up the exceedingly weak 
current received from the first tube, usually called 
the detector tube. By means of such a stepping 
up process, it is possible to bring in signals over 
tremendous ranges, a thing impossible to do with 
any other detector known at this time. 



70 



RADIO FOR ALL 

TUNING DEVICES 



We have seen in previous chapters that each 
radio wave-length is dependent upon the length of 
wire of each aerial. If it were possible to make all 
serials of exactly the same length and capacity, and 
if all stations were transmitting at exactly the same 
wave-length, we would not need any tuning devices. 
Unfortunately this is not the case. When we install 




Wire winding 



Fio. 32. 



an serial, we cannot always make it of the length or 
capacity which we desire, but are hampered by phys- 
ical and geographical limitations. In other words, 
our serial is usually a compromise. On the other 
hand, the various transmitting stations all send on 
different wave lengths, and for that reason, many 
different tuning devices are used. One of these, 
and the oldest, is the Tuning Coil, shown in Fig. 32. 
This is nothing but an aerial wound upon a cardboard 
tube or other circular or square piece of insulating 
material. The tuning coil is simply an extension 



RECEIVING INSTRUMENTS 



71 



of the serial. Even though we have an aerial which 
is only 100 feet long, by attaching more wire to it 
in the form of the tuning coil, we thereby lengthen 
the serial. The tuning coil, as shown in the illustra- 
tion, is simply an insulated wire wrapped upon a 
cardboard tube, its size is immaterial. Tuning 
coils may be made in almost any size, from the small- 




est one wound upon a pencil, to the largest, as 
big as a barrel. The more wire we use, the more 
wave-length our tuning coil will be able to absorb, 
so to speak. Of course, in practice tuning coils 
are built for a certain capacity, all depending upon 
what it is to be used for. If, for instance, we have 
but a little serial and wish to receive from stations 
having a wave length of say 650 meters, a small 
coil about 6 inches long and 2 inches in diameter and 
wound with No. 24 B & S gauge wire will do nicely. 
The purpose of the slider is simply to add more or 
less wire to the serial; it is but an adjustment the 



72 RADIO FOR ALL 

same as, for instance, a rubber elastic that you 
stretch more or less to make it longer or 
shorter as you desired. It goes without saying that 
the slider of the tuning coil must touch the wire, 
as otherwise no connection would be made. In Fig. 
33, we show the simplest connection for a tuning 
coil. This, as will be seen, duplicates the connection 




Fro. 34. 



of the crystal detector. We have here merely add- 
ed the tuning coil in order to tune the circuit. By 
means of this tuning coil, it now becomes possible 
to tune out unwanted stations merely by moving the 
slider back and forth and so connecting more or less 
wire to the aerial. For instance, if two stations are 
sending at the same time, by moving the slider back- 
ward and forward it becomes possible to tune in or 
out the unwanted station, and listen only to the one 
we desire to hear. In Fig. 34, we show the same 
tuning coil, but with sliders. The two sliders are 
somewhat of an improvement, for the reason that 



RECEIVING INSTRUMENTS 73 

better tuning is accomplished with them. This is 
what is technically called a more balanced circuit. 
It is possible to still add more sliders to one tuning 
coil. Years ago, three-slider tuners were in vogue, 
but they are now no longer the fashion. 

LOOSE COUPLERS 

The Loose Coupler is another form of tuning 
coil and this instrument, which was formerly used a 
great deal more than at the present time, is really 
one of the best tuning devices known. Instead of 
using just one coil, as for instance the tuning coil 
just described, a loose coupler uses two coils one 
sliding into the other without touching. The 
loose coupler is an electrical transformer, as it has 
been found that if a radio current traversed one coil, 
another tuning coil standing close by would be af- 
fected, although no wire touched the first coil. This 
is termed an "inductive effect." In other words, 
the energy is radiated from one coil to another, the 
same as a stove radiates heat to objects that are 
close to it. 

As we just mentioned, the loose coupler is a 
transformer. The current that comes in over the 
terial in the form of radio waves is a high frequency 
current. By that we mean that waves swing back 
and forth very rapidly. It is the purpose of the 
loose coupler to change this energy into a more 
suitable form. We again take recourse to an anal- 
ogy. In Fig. 36 we show, by means of a lever ac- 
tion, the principle of the transformer. We are all 



74 



RADIO FOR ALL 



familiar with the lever action whereby a man who 
weighs only 150 Ibs. can raise a weight of 1000 Ibs. 
by means of the lever. Is he getting something for 
nothing in this case? Certainly not! You cannot 
get free energy, but the experiment in Fig. 36 sim- 
ply shows that force plus time may be transformed 
into something else. In this case the man who 



150 IBS. 




PRIMARY 



weighs 150 Ibs. is the force and the time is the inter- 
val that it takes him to reach from point A to point 
B. The two added together are sufficient to raise 
the 1000 Ib. weight, the distance from C to D. The 
longer the lever arm L, the more weight we can 
raise. Archimedes told us that "give him a long 
enough lever he could raise the earth from its 
hinges." Always providing that he has a sufficiently 
long lever and a fulcrum, or point of rest which is 
shown at F in Fig. 36. Summing up, we understand 



RECEIVING INSTRUMENTS 



75 



now that by means of a small weight we are able to 
lift a much heavier one. 

This analogy holds with our loose coupler, which 
we have shown in Fig. 35. The loose coupler has 
two coils; the primary, which is usually the outer 
tube, is always wound with a coarser wire, while 
the inner tube is wound with a finer wire. As in the 



Primary 
I 



Slider 




Slider 



Secondary 



Fia. 35. 

tuning coil we have a slider upon the primary, or 
if we do not use a slider we may have taps (connec- 
tions) taken at every few turns of wire, if we so 
desire. On the secondary also, we may have a 
slider or taps brought out, both of which are the 
same. The inner tube is made to slide back and 
forth upon sliding rods so that the degree of coup- 
ling, as we call it, may be changed. If the inner 
tube, called the secondary, is pushed into the outer 
tube, which we call the primary, we have a complete 
electrical lever system, as shown in our analogy Fig. 
36. The energy that comes into the primary is now 



76 RADIO FOR ALL 

raised exactly as the weight is raised by means of 
a lever, and we get a marked effect from the second- 
ary. The more we pull out the secondary tube, 
the less our lever action becomes. It is as if the 
man in Fig. 36 were to move down to the point F 
where it would become impossible for him to raise 
the weight at all, or even to budge it. By using 
the loose coupler, we do not get something for noth- 
ing any more than if we raise a stone by means of 
a lever. In both cases we perform work. In our 
loose coupler, the result as a rule is that we get 
louder and better signals. 

Reverting back to Fig. 35, the tubes of the tun- 
ing coil may be of cardboard, hard rubber or com- 
position, or any good insulating material. No steel 
or iron should be used in the construction of a good 
loose coupler. Its size is immaterial providing the 
proportions are right, this being determined by ex- 
periment. The important part is that the second- 
ary must come as close as possible to the primary. 
In other words, the diameter of the two tubes must 
be so that the secondary tube, when moved inside the 
primary will take up the entire air space without, 
however, touching the outer tube. The closer the two 
windings come together, the better it is. In Fig. 37, 
we show the simplest connection for a loose coupler, 
crystal detector and phones. Very good results are 
had with this circuit, and the loose coupler is partic- 
ularly efficient for tuning out interference to a cer- 
tain degree. It gives what is called sharp tuning, 



RECEIVING INSTRUMENTS 



77 



because if two stations operate at a close wave 
length, let us say one at 360 meters and another 
at 320 meters, the loose coupler will give very good 
results by reason of its sharp tuning. In this case, 
it will be possible to tune in either station, if in 
connection with the loose coupler we use an addi- 
tional instrument, namely the condenser, which we 




will describe presently. When the connections are 
made, as shown in Fig. 37, we must keep the second- 
ary all the way in, and then adjust the slider on the 
primary until we hear the signals well. We now 
slide the secondary in and out, more or less, and in 
doing so, we move the slider upon the secondary also, 
until we reach a point where signals are loudest. 
This point is different for every station to which 
we are listening. 



78 



RADIO FOR ALL 
VARIOMETERS 



Variometers, Fig. 38, are usually built by having 
one spherical winding rotating within another spher- 
ical winding, as shown in the illustration. Both, how- 
ever, are wound with the same wire. By moving the 
inside, which is called the rotor, the inductive effect 



Stater 




Rotor 



FIG. 38. 



between this and the other winding, which is called 
the stator, is changed. It acts exactly as a loose 
coupler, but is somewhat less complicated. It is, 
however, not used much in connection with crystal 
detectors, but rather with vacuum tubes where a fine 
balance is necessary. The same is the case with the 



RECEIVING INSTRUMENTS 



79 



Vario-coupler shown in Fig. 39, which is also used 
almost exclusively in connection with vacuum tubes. 
In this instrumentwe have an outer tube wound with 
a heavy wire, while the inner tube which rotates 
upon its axis is wound with a finer wire. 




Knob 

and 

dial 



Stator 



Fia. 39. 

CONDENSERS 

In a radio circuit, in order to do fine tuning, 
we must often take recourse to the condenser which 
instrument is used to do just what its name implies, 
viz., condensing the electric current. This is per- 
haps not exactly accurate, for there is no condensing 
done in radio work, but rather a storing up 
of energy. 

Consider Fig. 40. Here we have a spring which 
we compress by means of a weight. As soon as we 
take the weight away, the spring returns to its orig- 
inal position. What have we done? We have 



80 JRADIO FOR ALL 

simply stored energy into the spring. The elec- 
trical condenser is used in exactly the same way, 
viz., to store electrical energy. However, that is 
not its only purpose. Just as the spring may be 
used for other purposes besides that of storing me- 
chanical energy, so the electrical condenser may be 
used for other purposes also. 




A condenser is a capacity or a vessel in which 
electrical energy is stored. The simplest form of 
electrical condenser is shown in Fig. 41, where we 
have a metal plate A, a glass plate B, and another 
metal plate C. By means of this arrangement, we 
may store electrical energy upon the inside surfaces, 
on plates A and C. The larger we make the metal 
plates, the more electrical energy may be stored. 

The form shown in Fig. 41, is used in many con- 
densers today. The metal plates A and C may be 
any form of metal, such as, for instance, tin or metal 



RECEIVING INSTRUMENTS 



81 



foil, while the glass plate B may be replaced by a 
piece of paraffin paper. In other words, any good 
metallic conductors may be used if coupled with 
a good insulator. The better the insulator, the bet- 
ter the condenser will be and the greater its elec- 
trical capacity. In the commercial condensers, 
paraffin paper, varnished silk, sulphur, sealing com- 



Metal 
plate 



A 




Glass, B 



Metal 
plate, C 



pounds, or best of all, mica, is usually used. In 
Fig. 42, is shown a simple condenser; this is also 
shown opened up in Fig. 43. It is made by rolling 
together two strips of tinfoil between several strips 
of paraffin paper. The whole, when rolled together 
and assembled, becomes the condenser shown in Fig. 
42. By rolling it together, it takes up less room. 
This type of fixed condenser, as it is termed, is 
generally used to connect across the telephone re- 
ceivers; this will be described in a later chapter. 
The purpose of this little condenser is to store up 



82 RADIO FOR ALL 

the electrical current and then discharge that cur- 
rent into the telephone receivers when the condenser 
becomes full, so to speak. If you will refer to our 
spring analogy you will readily understand the 
principle, and how it operates. In radio work, 
where fine regulation is required, we make use of 
still another condenser, as shown in Fig. 44. This 
condenser, instead of being fixed, is variable. As 




will DC seen, there are a number of plates which are 
usually made of zinc or aluminum, which mesh into 
each other to a more or less degree. The more 
plates we have and the closer they come to each 
other, the higher will be the capacity of that conden- 
ser. For certain purposes we need only a small 
condenser of a few plates, while in others we need a 
larger one of a great many plates. It is just like hav- 
ing a small spring and still another very large one. 
Both have their uses, and both are very necessary, all 
depending upon what work they are required to do. 
In Fig. 45, we show the simplest elementary con- 



RECEIVING INSTRUMENTS 83 

nection, where we have a crystal detector, a tuning 
coil without a slider, a pair of phones and a tele- 
phone condenser. This is a peculiar connection 
because in it we wish to show that we can tune by 
means of the condenser. As will be seen in this 
tuning coil, we do not use any slider by which the 
length of the serial may be changed, which would 



/- Waxed paper strips 



/m 

'/ 



\ AL. '.- . __ 





Tinfoil strips' 
Copper ribbon 



FIQ. 43. 

thus change the wave length. This is performed 
entirely by the variable condenser. When we ad- 
just the latter, we also change the relation of the 
tuning coil, and in fact we are changing the wave 
length until a point is found where the signals come 
in best. This is a finely balanced circuit, and the 
amount of wire on the little tuning coil should be 
in direct relation to the condenser. In other words, 
if there is too much wire on the tuning coil and the 
capacity of the condenser is small, we cannot do 
much tuning. For the best results, as for instance 
for receiving broadcast music on a wave length of 
360 meters, we could use a small coil, one inch in 



84 



RADIO FOR ALL 



diameter, wound with about 70 or 80 turns of No. 
18 enamel wire, while the condenser should be of 
the commercial variety known as a 23-plate conden- 




FIQ. 44. 

ser. Then, all we have to do is simply adjust the 
condenser until the signals are heard best. 

In this illustration, we also see where the phone 
condenser is located. This phone condenser stores 
the energy of the circuit, and discharges it into the 
telephone receivers which enables us to hear the 
signal more loudly. 

The two forms of condensers shown here are of 
course not the only ones, as many more types of 



RECEIVING INSTRUMENTS 85 

either fixed or variable condensers are made. How- 
ever, all of them are practically the same, roughly 
speaking, and so it is not necessary to enlarge 
upon the subject which is now well understood by 
the reader. 

VACUUM TUBE ACCESSORIES 

We have learned something about the vacuum 
tube which was described previously in this article, 
and in Fig. 31 we have shown the simplest connec- 
tion of an audion detector. There are, however, a 
number of other auxiliary instruments used in va- 
cuum tube systems which give certain refinements. 

The vacuum tube, when it is used singly, acts as 
a detector and detects the signals the same as a crys- 
tal detector. Also, we might state here, that the 
crystal detector is a better rectifier "valve" than 
the vacuum tube. The vacuum tube itself 
only becomes of great importance when used 
in special circuits. 

With a crystal detector, or in the ordinary sin- 
gle vacuum tube circuit, the incoming signals act 
upon the phones and we hear the signals with a cer- 
tain strength. Let us now consider the vacuum 
tube and the incoming signal. We may indeed, 
by certain means, boost up the very weakest of sig- 
nals and amplify or magnify it a hundred or a thou- 
sand or a million times its original strength. It is 
just as if you take a piece of film such as is used 
in a moving picture theatre and examine it with 
your eye. The figures are so small that you can 



86 



RADIO FOR ALL 



hardly distinguish them. The regular film which is 
about the size of a postage stamp here stands in our 
analogy as a single vacuum tube. We can, how- 




Fio. 45. 

ever, take that film, and by using a powerful light 
enlarge the little picture (no larger than a postage 
stamp,) by projecting it upon the screen. We 
thereby amplify or magnify the original picture 
several thousand times. We can amplify or en- 



RECEIVING INSTRUMENTS 87 

large it a million times if necessary, all depending 
upon the amount of light we put behind a film and 
the distance from the screen. This is graphically 
shown in Fig. 46. 

We may do precisely the same thing with a va- 
cuum tube, but we must use additional energy, the 
same as in our film where we use energy (the elec- 

SCREEN 








, I k ftR*tf AMPLIF1EDT 

(B BATTERY) ^AYE; WAVE J 

Fio. 46. 

trie current which produces the light) to project 
the film upon the screen. In other words, we can 
take the detector tube and enlarge the original small 
and weak signal, and boost it up until the sounds 
come out loud from a loud speaking horn, which 
in our analogy stands for the moving picture screen. 
The electrical connections for a vacuum tube ampli- 
fier are shown in Fig. 47. This is what is called 
technically a two-step amplifier. We show this 
connection simply because without it, it is almost 
impossible to bring home the meaning of the va- 
cuum tube auxiliary instruments with which the 
reader is as yet unfamiliar. In this circuit we have, 
as before, the serial, the ground, the variable conden- 
ser, the blocking or phone condenser and several 



88 RADIO FOR ALL 

other instruments as well. We find, for instance, 
that several transformers are used, viz., what is tech- 
nically called the Audio Frequency Transformer. 

AUDIO FREQUENCY TRANSFORMER 

This transformer, Fig. 48, consists of just an 
iron core upon which is first wound a coarse wire 
termed the primary, and on top of this a finer wire 




A- Variable condenser; B-Gnd leaKand condenser; C-Vario-couplen 
D- Detector tube; E- Amplifying transformer; F-Amplify/ng tube; 
G- Rheostat; H- Storage battery; J-B" batteries; K- Receivers; 
L- Horn; 



Fia. 47. 

termed the secondary. The ratio of these trans- 
formers is usually such that, electrically speaking, 
the value of the secondary is about ten times as 
much as that of the primary. The audio frequency 
transformer is in principle the same as the loose 
coupler, which we studied before, and the purpose 
of the audio frequency transformer is to transform 
the energy from a low level to a high one. The 
purpose of this transformer, as shown in Fig. 
47, is to boost up the weakest signals, trans- 



RECEIVING INSTRUMENTS 



89 



forming them into stronger ones. The trans- 
former by itself could never accomplish this, and 
in order to make the lever action work perfectly, 
we take recourse to a battery which is connected to 
the transformer and with the vacuum tube, as shown. 
By means of this additional electrical energy we are 
now in a position to boost up and relay the weak 



Secondary 




Iron core s Primary 



Fia. 48. 



signal. In this connection, we have shown first a 
detector tube, while the other tubes are amplifier 
tubes. By this we mean that the first tube receives 
the signal, while the other tubes are merely used as 
pumps to boost up the electrical energy until the 
signal finally comes from the phones so loudly that 
if we connect the phones with an ordinary sounding 
horn, loud signals or music will issue from the horn. 
The battery used in this case is a so-called "B" bat- 



90 RADIO FOR ALL 

tery, or high voltage battery which has been found 
necessary to aid in boosting up the weak signals. As 
a rule batteries anywhere from 24 to 300 volts are 
used, all depending upon the circuits and the pur- 
pose for which they are used to boost up the 
weak signals. 

It should be understood that the audio frequency 
transformer is used only to boost up the weak sig- 
nal as it leaves the first detector tube. It is not 
in the province of this transformer to do anything 
save amplify the signal which is detected by the 
detector tube. In other words, if outside inter- 
ference or static comes over the serial, the trans- 
former amplifies these noises as well. This trans- 
former, therefore, acts only as a sort of pump in- 
creasing the pressure, but it has no control over 
the flow that is pumped to the next tube. We shall 
see further where another sort of transformer may 
be used to obviate some of these difficulties. 

RHEOSTATS 

In Fig. 47, we also find another new instrument, 
the Rheostat, shown in detail in Fig. 49. This is 
simply an electrical resistance and is used solely to 
increase or decrease the glowing of the vacuum tube 
filament. When signals are received, it has been 
found that the filament must glow at a certain in- 
tensity. Some signals come in best when the fila- 
ment is burning very brightly, while with other tubes 
the signals come in best when the filament is only of 
a cherry red. This depends upon the make of the 



RECEIVING INSTRUMENTS 91 

tube and the vacuum of the tube itself. The rheo- 
stat is, therefore, simply an accessory to regulate 
the filament's incandescence. 

GRID LEAK 

In Fig. 47 we have another newcomer, which 
is termed the Grid Leak, and its condenser. It has 
been found that when the grid condenser is used, 



Contact 
blade 




stance wire wound on fiber strip 




REAR VIEW 



FRONT VIEW 



as shown in the illustration the signals will come 
in about twice as well as if none was used. How- 
ever, this condenser alone would not be sufficient, 
for the reason that the accumulation of electrons, 
which are highly charged electrical particles on the 
grid of the vacuum tube, would interfere with the 
normal working of the tube. We must provide 
a means to let the surplus electrons leak out without, 
however, letting them out too quickly. It is as 
if we had a boiler under which a constant fire was 
maintained. In order to provide a remedy, we in- 



92 RADIO FOR ALL 

stall a safety valve. This valve is used for the pur- 
pose of giving off the surplus steam and so keep the 
boiler free from harm. It is the same with the va- 
cuum tube. While of course, the vacuum tube 
would not burst, even if we did not use the grid 
leak, electrically speaking, the tube would not func- 
tion properly. Hence, the grid leak, which is a sort 




Fia. 50. 

of safety valve to let the surplus accumulation of 
electrons run off. The grid leak is nothing but a 
very high resistance, sometimes millions of ohms 
high. It may consist of only pencil lines drawn 
across a piece of stiff Bristol board; These pencil 
line are but slight electrical conductors, but the re- 
sistance is enormous. It suffices, however, to allow 
the surplus electrons to leak off. There are various 
ways and means to make grid leaks, and a popular 
form is shown in Fig. 50. Here we have a piece 
of cardboard or fibre upon which is traced a fine 
line in India ink. This line acts the same as a pencil 
line. The whole is enclosed in a tube to prevent 



RECEIVING INSTRUMENTS 



moisture or dust from settling upon the grid leak. 
Connections are made on the ends by metal clips. 
Fig. 51 shows a grid leak and condenser combined 
as two instruments, which are usually used in con- 
junction. The grid leak condenser is small and is 
similar to a telephone blocking condenser, and the 
grid leak is traced by means of China ink upon a 
piece of fibre ; the whole is enclosed in waxed paper. 




Assembled Grid LeaK 
and Condenser 



Vtoxed paper 
Tinfoil 



Metal 
eyelet 



India inK or 
lead pencil 
line. 




"Tinfoil f 

Waxed paper 



Grid leoK 
Method of Assembling 



Fio. 51. 

RADIO FREQUENCY TRANSFORMER 

In Fig. 47 we have learned all about the audio 
frequency transformer. We know that this trans- 
former amplifies static and also other disturbances, 
as well as the signals. For that reason it is not 
possible to use many such transformers, or, techni- 
cally termed, many steps of audio amplification. If 
we use more than three such transformers and their 
respective vacuum tubes, additional noises are all 



94 



RADIO FOR ALL 




RECEIVING INSTRUMENTS 95 

amplified, and the amount of noise which we get in 
the phones is tremendous. For that reason, we take 
recourse to what is termed a Radio Frequency 
Transformer, which is shown in the hook-up, Fig. 
52. The radio frequency transformer may consist 
of only two windings, one adjacent to the other on 
a cardboard tube. The simplest form is shown in 



Primary winding 




Secondary winding 



Fig. 53. The wire used on this is usually exceed- 
ingly fine, No. 40 B & S wire, or even thinner. The 
two windings act upon each other by induction, 
and do not make connections physically. In Fig. 
52, the first tube is an amplifier, and this amplifies 
the weak signals as they are coming in over an asrial. 
The radio frequency transformer steps up these 



96 RADIO FOR ALL 

weak signals, amplifying them and passing them on 
to the detector tube. We now get the net result, 
with the detector tube in a position to detect already 
fairly strong signals which may then be amplified in 
the audio frequency amplifiers, and boosted up 
further by a second or a third transformer, if so 
desired. We do not necessarily stop here because 
we may use more than one radio frequency trans- 
former; we may use two or even more. As this, 
however, brings us into higher technicalities, we will 
not go further, beyond showing the principle so that 
the reader may grasp the difference between the two 
kinds of transformers. 

To resume, and in a few words, we may say that 
the radio frequency transformer boosts up the very 
weak radio frequency currents so that the detector 
gives maximum results, whereas the audio fre- 
quency boosts up the audible signals. The radio 
frequency transformers, in other words, amplify sig- 
nals that would be lost otherwise, while the audio 
frequency transformers give volume to signals 
which are already audible. 

TELEPHONE RECEIVERS 

In order to receive signals or broadcasted enter- 
tainment by ear, we use a telephone receiver, of 
which two simple types are shown in Fig. 54 ; this 
consists of the following: First we have a power- 
ful magnet which attracts to it a thin iron dia- 
phragm. This diaphragm is clamped tight like a 
drum head along its outer edge. Upon the magnet 



RECEIVING INSTRUMENTS 



97 



are mounted two pole pieces around which are 
wound many thousand turns of exceedingly fine 
wire, almost as fine as the human hair. 

Ordinarily when no current is sent into the tele- 
phone receiver, the diaphragm is pulled down some- 
what to the pole pieces, although it must never touch 
them. If it does, no sound will be received. If, 
however, a weak electrical current passes through 



Diaphragm 



Pole pieces 




Fio. 64. 



these spools, the diaphragm will either be pulled 
down more if the current is in the right direction, 
or if the current is in the wrong direction, it will 
weaken the magnetism on the pole pieces. In this 
case, the diaphragm is not attracted. These little 
variations make the diaphragm vibrate more or less. 
These vibrations are passed on to the air, and the 
air vibrating in unison with the diaphragm is 
changed into sound waves, which are sent on to our 
ear, where we hear them. A telephone receiver is 
a marvelously sensitive instrument, and it is possi- 
ble with it to detect currents of less than one mil- 



98 RADIO FOR ALL 

lionth of an ampere and less than one hundred thous- 
andth of a volt. It is, therefore, an ideal instru- 
ment to detect the weak radio signals as they come 
over the serial. 

In radio we usually use two such receivers, which 
as a rule are provided with a head piece or 
head gear; this is slipped over the head, pressing 
the two receivers against the ears. It has been 
found that two receivers are better, because no out- 
side noises reach the one ear, as would be the case 
if one receiver only was used. 

Receivers for radio purposes should be wound at 
least to 1,000 ohms, or better to 2,000 ohms, and for 
certain other purposes to 3,000 ohms and higher. 
Telephones wound to 75 ohms such as the usual re- 
ceiver used on our house telephones are of no value 
for radio. Their resistance is not high enough, not 
even in connection with a crystal receiver. 

A good head set should give an audible click in 
the ears, if the two cord tips at the end of the cord 
are tapped upon the tongue. 

LOUD SPEAKERS 

In Fig. 55 is shown a Tone Amplifier or loud 
speaker known by its trade name as the Magnavox. 
This loud speaker works upon a principle where a 
small coil, through which the received current flows, 
is influenced by a powerful electro-magnet. It is 
another case of boosting up the sound which is re- 
ceived from the last amplifier tube. Such tone am- 
plifiers can throw the voice or music over distances 



RECEIVING INSTRUMENTS 




100 RADIO FOR ALL 

of one-half mile and more, and if a person stands 
in front of one of these giant horns, the amount of 
sound that issues from it is simply terrific. Of 
course, not all tone amplifiers work so loudly. Those 
made for home or parlor purposes do not use so 
much current, and therefore do not give so much 
power. There are a number of types of tone ampli- 
fiers, but most of them work along the same electro- 
magnetic lines, and if they do not use the outside 
battery in order to create a strong electro-magnetic 
field, they either use strong magnets to accomplish 
the same result, or necessitate the use of a very high 
tension battery in the amplifier. Such tone ampli- 
fiers are nothing but transformers or relays, trans- 
forming or relaying a weak sound into a loud one. 
As a matter of fact, most tone amplifiers rely upon 
acoustic means as well, all of them requiring some 
sort of horn, without which only mediocre results 
are achieved. The horn itself, is an acoustic ampli- 
fier, as anyone knows who has ever talked through 
a megaphone. Due to the echoes set up inside the 
walls of the horn, the sound is thus amplified. 



CHAPTER VI 
TUNING 

IN former chapters we learned something about 
tuning ; this is nothing but resonance. We all know 
the experiment of standing near the piano and sing- 
ing a certain note into it ; when we reach the correct 
or fundamental note, the piano begins to sound that 
particular note in sympathy. We may then say 
that we are in tune with that particular string which 
sounds in our ears. Likewise in radio, we make 
use of a similar system, except that we use electrical 
tuning instead of acoustical tuning. Tuning con- 
sists as a rule in merely attuning our serial electri- 
cally to the same length as the aerial that is trans- 
mitting to us. In other words if a broadcasting 
station is transmitting on a wave of 360 meters, 
we must attune our aerial to the same wave, 
namely, 360 meters. If we have an aerial which 
is 260 meters long, electrically speaking, it 
stands to reason that we must add 100 meters 
to this aerial in order to receive the wave at all. We 
have learned in other chapters how this may be ac- 
complished. If we have a receiving outfit, all we 
have to do is move the slider of our tuning coil back- 
ward and forward until the signals come in at maxi- 
mum strength. When that point is reached, we 
know that our aerial, electrically speaking, must be 

101 



102 



RADIO FOR ALL 



360 meters long. We have also seen in Fig. 45 that 
we need not have sliders on the tuning coil in order 
to tune. We may use a condenser for tuning pur- 
poses because its electrical equivalent is the same 
as a tuning coil slider. By adding more or less 
capacity to the condenser and therefore to the tuning 
coil, we change the electrical value of the tuning 




coil, and also its wave length. This is not literally 
true, technically speaking, but we must use this lan- 
guage to bring home the meaning. 

We therefore learn that we may tune either by 
lengthening the serial with additional wire, or by 
using a capacity or condenser in connection with a 
wire coil. Both, if correctly apportioned, give the 
same results. Before we can receive signals, or am- 
plify them, it is of the greatest importance that we 



TUNING 



103 



tune in to the right wave length. An aerial must be 
in electrical sympathy with the sending station be- 
fore we may hope to receive signals. In Figs. 56 
and 57, we have shown the elemental methods of 
tuning. Of course, there are many other ways of 
tuning, all of which, however, are along the same 
principles as those just enumerated. For instance, 
we have seen where we tune with a loose coupler. 




Fio. 57. 

This, however, is exactly the same as if we were 
tuning with a tuning coil. As a matter of fact, as 
we mentioned in the previous chapter, referring to 
the loose coupler, this latter instrument is nothing 
but two tuning coils, one sliding into the other. In 
the variometer, also, we have a sort of loose coupler 
with which the tuning is accomplished by changing 
the inductive relation between the two coils. This 
acts similarly to the tuning coil slider because the 
two coils either assist or else buck each other. Elec- 



104 RADIO FOR ALL 

trically speaking, therefore, the variometer or the 
variocoupler, either add wave length to the serial or 
subtract wave length from the serial. This is only 
figuratively speaking and mentioned here in order 
to drive home the point to the reader. 

In a vacuum tube set, many people think that 
when they adjust their detector tubes, their ampli- 
fier tubes or their rheostats, they are tuning in. 
This is erroneous because there is no tuning done in 
these instruments at all. We have learned that 
amplifying tubes simply belong in a pumping sys- 
tem which does not do any tuning at all, but simply 
amplifies the signals already received and tuned. 
It should, therefore, be remembered by the reader 
that tuning is only done directly in the serial system, 
never in the outside circuit. Of course, it goes with- 
out saying that there are circuits which are balanced 
in such a way that they are again influenced by the 
tuning, and vice versa. Therefore, if the two cir- 
cuits are out of balance, both must be adjusted in 
such a way that fine tuning becomes possible. 

Perhaps an analogy in tuning will not be amiss 
here, and we have a particular analogy that covers 
tuning nicely. Take the musical instrument, the 
trombone shown in Fig. 58. You all have seen this 
instrument, as nearly every orchestra boasts of one 
or more. It is known by all of us that while the 
musician blows into the mouth piece, he varies the 
length of the trombone by moving the sliding mem- 
ber back and forth. If he wants to get a deep note, 



TUNING 105 

he pulls the sliding member almost all the way out, 
and this gives him a long sound wave. If he wishes 
a high note, he must have a short sound wave. This 
means that he must push the sliding member all the 
way in. It is literally, as well as scientifically, true 
that the lengthened trombone gives a long wave 
length, while the shortened trombone gives a short 
wave length. These are, of course, sound waves 
with which we have to do here. In radio we do 





LONG SOUND WAVE LENGTH SHORT SOUND WAVE LENGTH 
Fw. 58. 

exactly the same thing in tuning. When we wish a 
long wave length, we must add more wire or its 
equivalent to the serial. If we want a short wave 
length we must either have a short serial or subtract 
some wire from the serial. To lengthen an aerial 
in order to obtain a greater wave length, we have 
seen before that we make use of a tuning coil and by 
means of the slider which we slide up and down, 
we increase the wave length just as the trombone 
player does with his instrument. To shorten the 
wave length in tuning, it would not be possible to 
shorten the serial, as this would be a cumbersome 
method ; of course it can be done, but not in actual 
practice. We, therefore, have recourse to a con- 
denser. The reader should remember that in order 



106 



RADIO FOR ALL 



to decrease the wave length of an serial, all that is 
necessary is to put a condenser in series with the 
serial which actually decreases the wave length; it 
does not increase it as some people seem to think. 
To make this clear, although it is not absolutely and 
literally true, just imagine that the condenser in the 
aerial circuit, as shown in Fig. 59, acts as a sort of 



To end ' . 

of coil / 

Tuning coil 




buffer which absorbs a portion of the wave length. 
The less condenser we add to the serial, that is, the 
less capacity we interpose in the serial circuit, the 
lower the wave length will be. The condenser, 
therefore, gives us the best practical means to de- 
crease the wave length ; this point is quite important 
to remember. Suppose you have a long aerial, say 
200 feet, in connection with a small tuning coil, or 
suppose you have a short serial and live on the tenth 
floor of an apartment house. The only available 
ground would be the water pipe. This water pipe, 



TUNING 



107 



however, would be so long that it would add extra 
meters to your wave length, and something must 
be done to decrease it, if you wish to receive signals 
sent out from a broadcasting station operating on 
a short wave length of 360 meters. The only way 
you could then tune in would be in the former case 
of the long serial, to put a variable condenser 




in the serial circuit, or in the other case where you 
have a long ground to interpose the condenser 
in the ground lead as shown in Fig. 60. As a 
rule, in these two instances, at least what is techni- 
cally called a twenty-three plate variable conden- 
ser should be used. Of course, the tuning coil must 
be used as well, but it should be adjusted so that it 
is at its lower point. In other words, it should not 
add more turns of wire to the serial, which would 
again increase the wave length. In most cases, a 
few turns will do, depending upon how long your 
jerial or lead-in is. 



CHAPTER VII 
TRIALS, LOOP TRIALS, GROUNDS 

WE have had occasion to speak of serials and 
grounds before, and we will now go into this inter- 
esting study more thoroughly. An serial is used to 
intercept radio waves ; that is its sole function in the 
receiving set. It does not amplify or make the sig- 
nals come in clearer by itself. During the past 
twenty-five years hundreds of different serials have 
been invented, and there is hardly anything in this 
field that has not been tried out. An serial, pro- 
perly speaking, is an elevated wire that is well insu- 
lated, and is usually placed outside of the building 
or house. An serial is one of the most important 
parts of a radio installation and should never be 
thought of in the light as an unimportant adjunct. 
As we said before, the serial has the function to 
intercept radio waves. These waves come from 
afar, and are often very weak and far apart, and in 
order to intercept the waves at all, it is of great 
importance that the aerial be of good construction. 

If you desired to catch butterflies, you would not 
use a net with large holes, because you would know 
in advance that with such a net you could not 
catch many butterflies. Likewise, if you wish to 
catch all the available waves that pass your house or 
abode, you must have an serial that does not allow 
the trifling energy that you have to leak out. Using 

108 



TRIALS, LOOP AERIALS, GROUNDS 109 

another and a very good simile, you would not think 
of pouring a very precious liquid into a sieve if you 
wanted to preserve all that precious liquid. You 
would use a good container without any holes in it. 
Just so with the serial. Always remember that a 




TO SET 



TO GROUND 



Fio. 61. 



chain is no stronger than its weakest link. Con- 
versely a radio outfit is no better than its serial. 

An serial can be made of most any metallic wire, 
but the best material is either copper or copper-clad 
wire, which is copper wire with a thin iron core. A 
still better wire to use is a stranded wire, which is 
composed of several copper or phosphor bronze 
wires twisted together. As a rule, we may say that 
the larger the wire, the better it is for radio purposes. 
Very thick wires, as a rule, cost much and are very 



110 RADIO FOR ALL 

heavy, and therefore are not very practicable. A No. 
14 B & S gauge wire is a standard as used today and 
gives excellent results. For radio broadcasting re- 
ception it has been found that a single wire 100 feet 
long gives excellent results. Illustrations 61 and 62 
show such a type of aerial. The single aerial is prefer- 
ably used, because its construction is much simpler 
than that of a four-wire aerial which we will describe 



-INSULATORS- 
IOO FEET LONG 




later on. If it is desired to receive from a certain sta- 
tion, the wire should point in the direction of that 
station ; in other words, if, let us say you live in New 
York, and you wish to hear WJZ at Newark, N. J. 
(which is west from New York) run your aerial wire 
from west to east. The lead-in from the aerial (the 
wire connecting the aerial to the outfit) should be 
connected to that end of the aerial nearest to Newark. 
The free or open end of the aerial, therefore, points 
away from Newark ; this is correct, as shown clearly 
in Fig. 63. This is a perspective view showing on 
which side the lead-in, that is the connection that 



TRIALS, LOOP AERIALS, GROUNDS 111 

goes from the aerial to the instrument, should 
be placed. 

Unless you wish to go to a great deal of incon- 
venience, make your lead-in of the same wire as the 
main aerial. This may be done very simply with a 




TRA 

STATION 



INSULATOR 




Fro. 63. 

single wire serial, for the reason that no soldered 
connections are necessary. This is also shown 
in Fig. 61 and Fig. 62. The next things to 
consider are the insulators, which are quite impor- 
tant. The insulator serves to insulate the serial, 
and unless we use good ones, a great deal of 
energy will leak and thus weaken the recep- 
tion. This is particularly the case in rainy weather 
where the water, or sometimes sleet, will make a 



112 RADIO FOR ALL 

semi-conductor and unless the insulator is con- 
structed correctly, much leakage will be the result. 
We show in Fig. 64* various types of insulators that 
may be used. One of the simplest is the ordinary 
porcelain cleat, but when this type is chosen, an 
unglazed cleat should be avoided. Insist upon get- 



Vorcelain cleats in tandem-^ 
Steel eyes 

\ 



Corrugated insulator 



Ti^s^s // /' ^r^ 

Porcelain strain^ Corrugated ^ 
insulator ball insulators 




FIG. 64. 



ting a glazed cleat which is a better insulator. When 
using cleats, put them in tandem, two or three strung 
in a row, as shown in Fig. 64. The more insulators 
we add, the better the insulation. It is however, 
hardly necessary to use more than three in a row. 
We next have the small spool insulators, which are 
very good and may also be strung in pairs, or sets 
of three. Various other types are shown in Fig. 64 
and regular radio insulators provided with ribs or 
under cuts are preferred these days, because they 



AERIALS, LOOP AERIALS, GROUNDS 113 

make a longer pathway for the electric current, and 
are, therefore, better insulators all the way through. 
It may be said here that the longer the aerial insu- 
lator, the better the aerial. The mode of fastening 
some of these insulators is shown in Fig. 64. The 
aerial is usually attached to the insulator, while the 
wire is twisted around itself after going through the 
hole in the insulator. Such radio insulators as a 
rule are quite strong, and when the serial is put up, 
it can be well stretched without fear that the 
insulator will give way. As a matter of fact, the 
wire will give way long before the insulator, if the 
latter is perfect. 

When putting up an serial, it should be remem- 
bered always that the aerial proper must be at least 
a foot away from all buildings, barns, trees and the 
like. In other words, it should be away from all 
objects, whatever their names may be. In order to 
do so, it is often necessary to attach a wire to a cor- 
nice of the building, let us say, and .extend the wire a 
few feet, to which we connect the insulators. The 
aerial proper is then connected to the other end of the 
insulator, which will give us a certain distance be- 
tween the cornice and the actual beginning of 
the aerial. 

The height of the aerial is often important. It 
should always be placed at least 20 to 30 feet above 
the ground. Generally speaking, the higher the 
aerial, the better the reception. High poles are not 
always necessary, although very often a good in- 

8 



114 



RADIO FOR ALL 



vestment. Such poles, however, as a rule are expen- 
sive and most people do not wish to go to such an 
expense. If poles become necessary, they should 
be put up by someone who knows something about 
the erection of poles, because if not put up correctly, 
such a pole becomes a dangerous object when it 




LIGHTNING SWITCH 



collapses from its own weight or in a storm. Good 
engineering in pole construction is a prime necessity. 
As a rule, an asrial in the country may be 
stretched from the attic window to a flagpole, or if 
such is not at hand, a barn, garage, or even a tree 
could be made use of . If a tree is used, some means 
must be had to compensate for the swaying of the 
tree. Such a method is used in Fig. 65. Here we 
have a pulley attached to a tree by means of a rope ; 
the end of the serial is then run over this pulley and 
a fairly heavy weight secured to the open end, such 



AERIALS, LOOP AERIALS, GROUNDS 115 

as an old pail filled with stones. As the tree sways 
back and forth, more or less serial rope is paid out or 
taken in, and a good compensation is thus had. The 
weight may be 50 to 100 pounds, and an arrange- 
ment of this kind works very well. It goes without 
saying that the pulley must be insulated by insula- 
tors, all of which is shown in Fig. 65. 

When an serial is erected in the city, let us say 
on an apartment house, we usually do not have 
much trouble in putting up a good wire, providing 
the landlord does not object, and few landlords do 
these days, as they' are becoming more and more en- 
lightened in radio matters. The only thing-that we 
may add is that an apartment house serial should 
be at least 10 feet above the roof, particularly if 
the apartment has steel in its construction. If we 
can put up an aerial higher than 10 feet, so much the 
better. The aerial should always be stretched taut, 
as a sloppy and saggy serial is not only unsightly, 
but gives rise to poor reception. See Fig. 62. The 
reason is that a saggy serial will swing in the wind, 
and it has been found that such an serial will not 
bring in sharp signals, due to this very swinging. 
It often gives rise to what is called "fading signals," 
in other words, one minute the signals may be clear 
and the next minute they will be faint. 

For long distance work, and where we have a 
very good outfit that has good tuning, we often use a 
larger serial, i.e., an serial that gives us more capac- 
ity; to be more explicit, an serial that covers more 



116 



RADIO FOR ALL 



space than a single serial. In Fig. 65 and Fig. 66, 
and 66A, we have shown a two and four-wire serial 




TO GROUND 



Fio. 66. 



PULLEY TO RAISE 
AND LOWER AERIAL 




Fra. 66 A. 

of the inverted L type. These serials are simply 
duplications of the single wire serial, except that 
more wires are used. With such serials it is always 



AERIALS, LOOP TRIALS, GROUNDS 117 

necessary to solder the connections or otherwise use 
an antenna connector as shown in Fig. 67. The types 
of serial as shown in Fig. 65, 66 and 66A are com- 
monly called the inverted L, due to their similarity 
to the letter L, turned upside down. Such an aerial 
is directive, the same as a single wire aerial, as shown 
in Fig. 63. As in the latter, the inverted L type 




Fro. 67. 



must have its lead-in taken from the nearest point to 
the broadcasting station. The free end, therefore, 
points away from the station that we wish to hear. 
Fig. 68, shows a four-wire aerial. This aerial has 
no directive properties, and receives signals from 
many points of the compass almost equally well. 
The only difference here is that the lead-in is taken 
from the center of the aerial instead of from the end. 
An aerial of this kind may be shorter than a single 



118 



RADIO FOR ALL 



wire aerial, and the wire in this instance may be 40 
or 60 feet long, and excellent results may be had 
with such a type. Where we have a multiple wire 
serial, a new element comes into its construction, viz., 
the Spreader. This is simply a stick of wood, well 
painted to keep it from decaying, upon which the 



PULLEY 




STAY ROPES 



-POLE 





LEAD-IN 



Fio. 68. 

insulators are strung, as shown in the illustrations. 
The wires themselves, should be spaced about two 
feet apart. The spreader must of course, be sub- 
stantial, so that it will not break under the tension. 
A bamboo stick about 1 inch or 1 ]/2 inches in diam- 
eter has been found to be ideal for this work. It 
is often necessary to take down the serial when 
we have poles, and for this purpose we use pulleys, 
as shown in Fig. 68, by means of which the serial 
may be raised and lowered when necessary. In 



TRIALS, LOOP AERIALS, GROUNDS 119 

Fig. 68 we also see two pieces of cord or rope at- 
tached to the spreaders which are put there for the 
purpose of keeping the serial from swinging side- 
ways or turning over as would be the result if there 
was nothing to prevent it. Therefore, stays 
are used. 

LEAD-IN 

The lead-in is that part of the asrial that goes 
into the building or house to establish connection 
with the instruments. In a single- wire serial, the 
lead-in is simply the serial wire itself leading into 
the house and thence to the instruments. With a 
two, three and four-wire serial, the lead-in is con- 
nected to the antenna connector described in Fig. 
67, and from that point runs on to the instruments. 
The lead-in wire should be of the same size as the 
aerial. In other words, about No. 14 B & S wire. 
It should be insulated at the point where it nears 
the building, or if this is not possible in the case of 
a single-wire serial, the lead-in is then strung on 
insulators, the wire being always at least one foot 
away from buildings, walls, etc., until it reaches the 
point where actual entrance is made into the build- 
ing; at this point several things arise. We may 
bring the wire in through the open window, which, 
however, is always considered bad practice. It 
should only be done for temporary work. One of 
the simplest ways is to drill a hole in the center of the 
window pane at the very upper part of the window, 
and let the wire come in through this hole, which, 



120 



RADIO FOR ALL 



however, is not such a good practice either, for 
the simple reason that it becomes impossible to 
lower the window, as the wire will obstruct it. The 
best way is to drill a hole through the sash of the 
window at any convenient point where the window 
weights will not be interfered with. This hole can 
be about three quarters of an inch. Into this hole, 




To . 

receiving^-)! 
set * I 



l,To aerial 

Insulating tube 
^ _ Drip for rain water 
ja^ Cross section of window sosh 




fit an ordinary porcelain tube which may be secured 
from any electrical supply house. The lead-in is 
then fed through this tube, and thence on insulators 
to the instruments ; Fig. 68- A makes this clear. If 
we do not wish to drill such a large hole through the 
window sash, a small one may be made instead, in 
which case, we must use a piece of rubber insulated 
cable, such as is used on automobiles and this is fed 
through the small hole. The actual lead-in wire is 
then soldered on the outside of the window to make 



/ERIALS, LOOP TRIALS, GROUNDS 121 

connection with the automobile cable so that no 
part of the bare wire touches the wood work or stone 
work near the window. The insulated rubber cable 
is then carried along insulators to the instruments. 
It should be remembered that the serial wire must 
always be well insulated, and that it cannot be insu- 
lated too well. Always bear in mind that we have 
but little energy coming in over the ferial, and the 
better we insulate the lead-in the better the results 
will be. 

We again wish to point out here that for radio 
telephone reception a single-wire aerial of 100 to 150 
feet long is always the best, whether used with a 
crystal outfit or with a vacuum tube set. The rea- 
son for this is not because the single aerial wire is 
inherently better, but because with it there is less 
interference on account of its directional properties. 
It has come to the author's attention that many peo- 
ple, when buying a small crystal set, are disappoint- 
ed because they are not able to receive signals, but 
do receive radio telephone concerts. Many people 
desire to receive signals as well, as for instance the 
Arlington time signals, market reports that are sent 
out in code, etc. To all these people we say that 
if they desire to receive signals as well as radio tele- 
phony, they should use a two or four-wire serial. 
They should, however, not complain if, when receiv- 
ing radiophone entertainment, signals come in at 
the same time ; this often happens with a two or four- 
wire aerial, and unless the instrument used is a very 



122 



RADIO FOR ALL 



selective one, it is not always possible to tune out 
the unwanted station that sends in code. This is 
especially true of crystal sets where it is impossible 
to tune quite so sharply as with vacuum tube sets. 




FIG. 69. 



There is still another type of serial that was used 
at one time extensively, and although it is not used 
so much today, it has a great deal of merit. We 
refer to the Umbrella .zErial as shown in Fig. 69. 
This serial as its name implies, is in the form of an 
umbrella, and may be made of any size, but should 
never be less than 25 feet high, 50 or 75 and even 
100 feet, being better. In the umbrella serial we have 



TRIALS, LOOP TRIALS, GROUNDS 123 

a single mast, from the top of which emerge single 
wires in all directions. The connections are made 
as shown in the illustration. This aerial has a great 
advantage in being able to receive from all direc- 




tions equally well. As we have noted before, the 
single-wire ferial receives with maximum intensity 
from one direction. The umbrella aerial, however, 
receives from all points of the compass with equal 
facility. It is also possible by a switching arrange- 
ment to connect any one of the serial wires of the 
umbrella antenna in order to get rid of interference. 
This means, of course, an elaborate switching ar- 



124 



RADIO FOR ALL 



MAXIMUM 
RECEPTION 




EPTION 




MAXIMUM 
RECEPTION 



X~MINIMUM RECEPTION 



rangement, which is not very often within the reach 
of the layman, by whom such an aerial is rarely, if 



TRIALS, LOOP AERIALS, GROUNDS 125 

ever used. To the man, however, who desires to go 
in for experimental work such an serial has its uses, 
and will repay the labor spent in constructing it. 

We now come to an serial which is entirely differ- 
ent from those of which we have spoken before. We 
refer to the loop aerial, which is shown in Fig. 70. 
It should be understood that a loop serial is hardly, 
if ever, used in connection with a crystal set. It 
is used almost exclusively with a vacuum tube set, 
as will be explained further on. The loop serial 
serves several purposes. In the first place it does 
away with the ground connection. Secondly, the 
loop serial may be made in any size from one foot 
square up to 20 feet square. The loop aerial is 
highly directive ; by that we mean that it will only 
receive with maximum intensity if the loop is turned 
in the direction of the coming signals. This is 
shown clearly in Fig. 71. Here we see how an or- 
dinary loop serial is placed in a building, and we also 
see how the waves are propagated from a distant 
sending station. It will be found that the signals 
are strongest when the loop points exactly in the 
direction from which the waves are coming. The 
loop aerial, therefore, serves the additional purpose 
of telling from which direction the waves are com- 
ing, and this principle is made use of in the 
radio compass. 

All the ships that come from points far away 
do not compute their own bearings any longer, but, 
by means of radio, call the nearest compass station. 



126 RADIO FOR ALL 

There are usually several of these stations placed 
at various points along the coast, and by means of 
their radio direction finder, the personnel at the sta- 
tion turn the loop until they hear the ship with maxi- 
mum intensity; the loop is then pointing directly 
to the ship. The station further down the coast 
does the same thing, while the two stations com- 







EM. 72. 

municate with each other by telephone or telegraph. 
By means of triangulation the operators then cal- 
culate within a few minutes just exactly where the 
ship is located. Within one or two minutes at the 
latest one of the land stations radios to the ship, tel- 
ling at what latitude and longitude it is ? The posi- 
tion can be ascertained within a few hundred feet, 
a thing impossible for any captain to do with his 
compass, or by other means. Fig. 73, shows the 
radio compass graphically. 



AERIALS, LOOP TRIALS, GROUNDS 



127 



As to the loop serial itself, as we have already 
mentioned, its size depends upon the builder. It is 
usually made up of a frame as shown in Fig. 70, 
and this frame may be from 2 to 4 inches square. 
Upon the frame are usually wound about six to ten 
turns of insulated wire, the two ends coming out 
somewhere near the center and connecting with the 



Loop 
aerial 



Vario-coupler 




Variable condenser 



Storage battery-^x 



Fro. 73. 

instruments. Fig. 72 shows the simplest connection 
of a loop aerial, with the simplest regenerative va- 
cuum tube hook-up. 

While in this diagram the loop aerial is shown, it 
should be distinctly understood that a loop asrial is 
not of much use unless we have at least two or three 
stages of amplification. The reason is that the loop 
asrial, being as a rule very small, its capacity is na- 
turally small, and but few waves strike it. There- 
fore, it becomes necessary to amplify the exceed- 
ingly weak currents. The connection shown in 



128 



RADIO FOR ALL 



Fig. 72 is only good if we are located but a few miles 
from the broadcasting station. For longer dis- 
tances, we must have several stages of amplification 
as already mentioned. Tuning with the loop aerial 
is rather difficult because, as mentioned before, the 
serial must point exactly in the direction from which 
the signals come. Moving the loop even a few 




Rubber insulated wire 
inside iron pipe .. ^- 



FIG. 74. 

inches to the side will cut off all the signals. The 
best position, therefore, must always be found 
by experiment. 

We come now to still another aerial which is the 
least used, but which has its advantages; we refer 
to the underground serial. Fig. 74 shows the prin- 
ciple, which consists of a well insulated wire, usually 
a rubber covered automobile cable. A trench about 
two to three feet deep is dug in a straight line run- 
ning in the same direction from which the signals 
are expected to be received. The wire is then care- 
fully insulated at the open end and run through an 



TRIALS, LOOP AERIALS, GROUNDS 129 

iron pipe. Both are then placed at the bottom of 
the trench. Such a wire must be at least 200 feet 
long to get fair results. After the trench is cov- 
ered over again the other end is led into the station, 
and connected with the instruments, the same as the 
usual serial. A ground must be used with this serial, 
which will only receive signals from the direction in 
which it points or points away from. It can of 
course not be used much in the city, but is desirable 
in the country if a pole or overhead wires are not 
wanted. The underground serial has the very great 
advantage of being almost entirely free from static 
and atmospheric disturbances. Thus, for instance, 
Dr. James Harris Rogers, the inventor of the under- 
ground serial during the war, received excellent sig- 
nals from Nauen, Germany, as well as other 
European centers while a thunderstorm was raging 
overhead. Of course, it goes without saying that 
an overhead serial cannot be used during a thunder 
storm because it becomes extremely dangerous to 
the user. With the underground serial such risk 
is entirely eliminated. 

Not only that, but in the summertime the over- 
head serials give quite a good deal of trouble, due 
to static and atmospheric electricity, even though 
there is a blue sky overhead. As we have already 
mentioned in another chapter, in the summertime 
the atmosphere is continually charged with electric- 
ity, and this electricity discharges through the serial 
wire and gives rise to crackling sounds in the re- 

9 



130 RADIO FOR ALL 

ceivers which often become unbearable. So far, 
nothing has been invented to do away with these 
parasitic currents, technically called X or static. 

How TO FIGURE WAVE LENGTHS OF 



Each aerial used for transmitting and receiving 
has a wave length of its own. It depends upon 
several factors beside its dimensions and it is prac- 
tically impossible to calculate it accurately unless 
a measuring instrument is used. The wave length 
depends upon the length of the wire composing the 
aerial taken from the ground to the free end of the 
wire. If it is composed of several wires, the num- 
ber and spacing of these wires also influence the 
wave length as well as the distance of the straight 
portion from the ground, and the shape of the 
aerial itself. 

The wave length of a single- wire aerial is, rough- 
ly, four times the length of the wire from the ground 
to the free end measured in meters. For instance, if 
a single-wire serial 100 feet long, is erected 50 feet 
above the ground with the lead-in that is vertical, the 
total length of the wire will be 150 feet or 45 meters. 
The wave length will consequently be 45X4= 
180 meters. 

The wave length of an aerial depends upon the 
nature of the ground above which it is erected and 
the objects interposed between the flat portion call- 
ed the flat-top and the ground. If an aerial is erected 
above the house, its natural wave length will be 
different from what it would be if erected in a field 



TRIALS, LOOP TRIALS, GROUNDS 131 

without any obstruction in the neighborhood. For 
this reason, no formula can be given that will be 
accurate enough to tell this, and the only practical 
means of measuring the natural wave length of an 
serial is by means of a wave meter. 



Natural Wave Lengths 
of 4 wire T aerials 




60 80 100 120 140 160 180 200 220 240 

Horizontal length of aerial in feet 



FIG. 74 A. 

The accompanying charts shown in Figs. 74A 
and 74B have been compiled by taking the average 
wave length of several serials of the same size erect- 
ed at different places and give sufficient accurate 
measurements for the ordinary types of antenna? 
used by amateurs. Fig. 74A shows the natural 
wave length of an serial of the "T" type, that is, 
those of which the lead-in is taken from the exact 
center. Above each curve is marked the height 



132 



RADIO FOR ALL 



from the ground to which it corresponds. Fig. 74B 
gives the wave length for serials of the inverted 
"L" type, that is, those having the lead-in taken 
from one end of the wires. The free ends of the 
serial wires are in both cases free. That is, with- 
out connections across on the wires. 



325 

300 

275 

250 

225 

200 

175 

150 

125 

100 

75 

50 

25 



Natural Wave Lengths 
of 4 wire inverted L aerials. 




30 40 50 60 70 80 90 100 110 

Horizontal length of aerial in feet. 



Fia. 74 B. 



To find out the wave length of an inverted "L" 
serial 100 feet long and 40 feet above the ground, 
we refer to Fig. 74B, and by means of a rule we 
measure on the scale indicating the wave length, 
how many meters correspond horizontally to the 
point where 100 feet in length crosses 40 feet 
in height. This gives us approximately 175 meters 
wave length. 



TRIALS, LOOP TRIALS, GROUNDS 133 

GROUNDS 

In radio, in connection with the usual aerial, it 
becomes necessary to use a ground, which, as its 
name implies, is a connection made with the earth. 
The earth being a good conductor, it is often used 
as a sort of return circuit, and it has been found, 
that, with the ordinary circuits, signals come in very 
much better if such a ground is used. It is possible 




FIG. 75. 



to use an aerial without a ground for short distances, 
in which case it becomes a sort of loop. For ordin- 
ary purposes, however, it would be impossible to 
use a radio outfit without a ground connection. 
Fig. 75 shows the simplest and perhaps the best. 
It is simply a wire fastened to the cold water pipe, 
which is found in almost every house and apartment. 
In order to make a good connection, we use a ground 
clamp, as shown in Fig. 76. This ground clamp 
is simply a piece of metal band wrapped around 



134 



RADIO FOR ALL 



the water pipe, which should first be scraped with a 
file or old knife, the idea being to obtain a perfectly 
clean metallic connection. By means of some 
clamping arrangement, which differs for every 
ground clamp, a strong mechanical connection is 
made. The ground wire is then fastened to the 
screw or binding post attached to the ground clamp. 



Wire 




Front > 
view 



The ground wire need not be insulated. An ordin- 
ary bare No. 14 B & S wire will do nicely; in other 
words, the same wire which we use on an serial may 
be used. It is not necessary to run the ground wire 
on insulators, as is done with the aerial lead-in, but 
it may be attached to the wall by means of nails 
which serve the purpose equally well. Of course, 
the ground wire should not be longer that is abso- 
lutely necessary. If it is not possible to find a cold 



AERIALS, LOOP TRIALS, GROUNDS 135 

water pipe, a radiator pipe may be used, although 
the results may not be as good as from the cold water 
pipe. It is against the law to connect a ground to 
a gas pipe, and it should therefore never be done. 
In the first place you encourage fire danger, and 
secondly the gas ground connection is never as effi- 
cient, for the reason that the pipe does not run di- 



BINDING 
POST 




POINTED 
END ~ 



rectly into the soil. Usually such gas pipes go first 
to a gas meter which, due to leather washers and 
lead paint, often insulate the pipe from the ground, 
and therefore the results with a gas ground are often 
very poor. For these reasons it is never advisable to 
use such a ground except in emergency, but never 
for permanent use. 

When we are out in the country, for instance, 
when camping, it is not always possible to have a 



136 RADIO FOR ALL 

water pipe, and in that case we have to establish 
contact with Mother Earth direct. This is usually 
accomplished by driving a metal rod into moist 
earth, as is shown in Fig. 77. A "ground" of this 
sort is nothing but an iron, brass or other metallic 
rod sharpened at the end and driven anywhere from 
18 to 36 inches into the soil. The wire to make con- 
nection may be soldered, or may have a binding 
post or a ground clamp just as on a water pipe. 
A ground of this kind will not work unless it is 
actually driven into the moist soil. It is thus neces- 
sary to do two things : first, we may pour a large 
quantity of water near the grounding rod to make 
sure that the earth becomes moist for quite a dis- 
tance surrounding the rod. Even by applying this 
artifice it is not always possible to obtain results 
because the underlying strata may be devoid of 
moisture, and it will then not be possible to receive 
signals; this is especially the case on many hill-tops. 
When such conditions arise, it becomes necessary to 
move the ground until we actually reach a wet spot 
such as, for instance, in the immediate vicinity of a 
natural well, the shore of a creek or a small body of 
water such as a pond or a lake; these all make 
ideal grounds. 

In farm houses where no water pipe exists it 
is usually best to drive a gas or water pipe from 
1 to 1 }/2 inches in diameter into moist soil. Connec- 
tion is established by means of a ground clamp, as 
already explained. 



AERIALS, LOOP AERIALS, GROUNDS 137 

The question is often asked how ships or motor 
boats can have a ground. The answer to this is that 
the ground connection is always attached to the 
outside metallic plating of the ship or motor hoat. 
The connection should always be soldered. Such 
a ground is really a very excellent one, and will 
always work. 

GROUNDS IN APARTMENT HOUSES 
It should be understood that there are grounds 
and grounds. The reason is as follows. A long 
ground, by reason of its length, has a certain effect 
upon the receiving outfit on account of its own wave- 
length. If we have but a short ground, say ten or 
fifteen feet long, its wave-length is minimum. But 
consider Fig. 78. Here we have an aerial, say 50 
feet long, on top of a ten-story apartment house. 
The owner of this outfit, let us say, lives on the tenth 
floor. If we trace the ground down to the soil, 
we will find a water pipe anywhere from 100 
feet to 120 feet long. What is the result? Such 
a long ground will add about 740 meters wave- 
length to the outfit, and will in fact, overshadow the 
serial to such an extent that the ground becomes 
longer than the serial. This is very poor practice, 
but it cannot, of course, always be helped. It has 
been found that where such an occasion prevails, 
the usual outfits sold on the market do not work very 
well because they are not built to operate on such 
a wave length. In order to use an outfit with such 
a long asrial, it becomes necessary to install a var- 



138 



RADIO FOR ALL 



iable condenser in series with the ground wire in or- 
der to overcome the handicap. See Fig. 60. By 
adjusting the variable condenser, a point will be 
found where the signals come in best. The conden- 



FAUCI 



00 



Q D 
DDDJ30D 
000300 
000000 

oo HOOD 



n 



nn 



.WATER 
PIPE 



STREET 



ser, in other words, cuts down the wave-length to 
a point where it counter-balances the excessive 
wave-length of the ground. Such a condenser 
should always be used when there is a long ground, 
as for instance, in apartment houses, high office 
buildings etc. 



2ERIALS, LOOP JERIALS, GROUNDS 139 

LIGHTNING ARRESTERS 

The properly installed serial, when used with a 
lightning arrester, is the best protection a building 
or house could have against lightning. Always re- 
member that the serial is nothing but a lightning 
conductor itself, and will actually protect the house, 
and will never endanger it if properly installed. 
An serial will draw the atmospheric electricity si- 
lently to the ground, and there are very few authen- 
tic cases on record where lightning has actually 
struck an serial. If it did strike it, it usually did very 
little damage because the lightning spent itself 
through the lightning arrester or lightning switch 
down to the ground. In former years, it was nec- 
essary to use a lightning switch by which, in a thun- 
der storm, it became necessary to connect the serial 
directly to the ground. Recent regulations, how- 
ever, make it unnecessary for owners of a radio re- 
ceiving outfit to have a lightning switch, although it 
is a good precaution and we give below the present 
Federal regulations for installation of lightning 
arresters. 

The lightning arrester itself is nothing but a 
small spark gap either in a vacuum or in the atmos- 
phere, which gap breaks down when a current of 
a few hundred volts strikes the serial. Instead of 
going through the instruments which have a high 
resistance, the current travels direct to the ground, 
which has a low resistance. Secondly, the instru- 



140 



RADIO FOR ALL 



ments are not damaged. In Fig. 79 are shown the 
various types of lightning arrester. Fig. 61 shows 
the connections. The lightning regulations follow 
herewith : 

RADIO EQUIPMENT 

In setting up radio equipment all wiring pertaining thereto must 
conform to the general requirements of this code for the class of work 
installed and the following additional specifications: 






Fro. TO. 

FOR RECEIVING STATIONS ONLY 

ANTENNA 

(a) Antennae outside of buildings shall not cross over or under 
electric light or power wires of any circuit of more than six hundred 
(600) volts or railway trolley or feeder wires, nor shall it be so lo- 
cated that a failure of either antenna or of the above mentioned 
electric light or power wires can result in a contact between the 
antenna and such electric light or power wires. 

Antennae shall be constructed and installed in a strong and durable 
manner and shall be so located as to prevent accidental contact with 
light and power by sagging or swinging. 

Splices and joints in the antenna span, unless made with approved 
clamps and splicing devices, shall be soldered. 

Antennas installed inside of buildings are not covered by the 
above specifications. 



TRIALS, LOOP TRIALS, GROUNDS 141 

LEAD-IN WIRES 

(b) Lead-in wires shall be of copper, approved copper-clad steel 
or other approved metal, which will not corrode excessively and in no 
case shall they be smaller than No. 14 B. & S. gage except that ap- 
proved copper-clad steel not less than No. 17 B. & S. gage may 
be used. 

Lead-in wires on the outside of buildings shall not come nearer 
than four (4) inches to electric light and power wires unless sep- 
arated therefrom by a continuous and firmly fixed non-conductor that 
will maintain permanent separation. The non-conductor shall be in 
addition to any insulation on the wire. 

Lead-in wires shall enter building through a non-combustible, non- 
absorptive insulating bushing. 

PROTECTIVE DEVICE 

(c) Each lead-in wire shall be provided with an approved pro- 
tective device properly connected and located (inside and outside the 
building) as near as practicable to the point where the wire enters the 
building. The protector shall not be placed in the immediate vicinity 
of easily ignitable stuff, or where exposed to inflammable gases or 
dust or flying combustible materials. 

The protective device shall be an approved lightning arrester which 
will operate at a potential of five hundred (500) volts or less. 

The use of an antenna grounding switch is desirable, but does not 
obviate the necessity for the approved protective device required in 
this section. The antenna grounding switch, if installed, shall, in its 
closed position, form a shunt around the protective device. 

PROTECTIVE GROUND WIRE 

(d) The ground wire may be bare or insulated and shall be of 
copper or approved copper-clad steel. If of copper the ground wire 
shall be not smaller than No. 14 B. & S. gage and if of approved 
copper clad steel it shall be not smaller than No. 17 B. & S. gage. 
The ground wire shall be run in as straight a line as possible to a good 
permanent ground. Preference shall be given to water piping. Gas 
piping shall not be used for grounding protective device. Other per- 
missible grounds are grounded steel frames of buildings or other 
grounded metallic work in the building and artificial grounds such as 
driven pipes, plates, cones, etc. 

The ground wire shall be protected against mechanical injury. An 
approved ground clamp shall be used wherever the ground wire is 
connected to pipes or piping. 



142 RADIO FOR ALL 

WIRES INSIDE BUILDINGS 

(e) Wires inside buildings shall be securely fastened in a work- 
manlike manner and shall not come nearer than two (2) inches to any 
electric light or power wire unless separated therefrom by some con- 
tinuous and firmly fixed non-conductor making a permanent separa- 
tion. This non-conductor shall be in addition to any regular insulation 
on the wire. Porcelain tubing or approved flexible tubing may be 
used fcr encasing wires to comply with this rule. 

RECEIVING EQUIPMENT GROUND WIRE 

(f) The ground conductor may be bare or insulated and shall be 
of copper, approved copper-clad steel or other approved metal which 
will not corrode excessively under existing conditions ; and in no case 
shall the ground wire be less than No. 14 B. & S. gage except that 
approved copper-clad steel not less than No. 17 B. & S. gage may 
be used. 

The ground wire may be run inside or outside of building. When 
receiving equipment ground wire is run in full compliance with rules 
for protective ground wire, in Section d, it may be used as the ground 
conductor for the protective device. 

FOR TRANSMITTING STATIONS 

ANTENNA 

(g) Antennae outside of buildings shall not cross over or under 
electric light or power wires of any circuit of more than six hundred 
(600) volts or railway trolley, or feeder wires nor shall it be so located 
that a failure of either the antenna or of the above mentioned electric 
light or power wires can result in a contact between the antenna and 
such electric light or power wires. 

Antennae shall be constructed and installed in a strong and durable 
manner and shall be so located as to prevent accidental contact with 
light and power wires by sagging or swinging. 

Splices and joints in the antenna span shall, unless made with 
approved clamps or splicing devices, be soldered. 

LEAD-IN WIRES 

(h) Lead-in wires shall be of copper, approved copper-clad steel 
or other metal, which will not corrode excessively and in no case shall 
they be smaller than No. 14 B. & S. gage. 

Antenna and counterpoise conductors and wires leading therefrom 
to ground switch, where attached to buildings, must be firmly mounted 
five (5) inches clear of the surface of the building on non-absorptive 



TRIALS, LOOP AERIALS, GROUNDS 143 

insulating supports such as treated wood pins or brackets equipped 
with insulators having not less than five (5) inch creepage and air 
gap distance to inflammable or conducting material. Where desired, 
approved suspension type insulators may be used. 

(i) In 'passing the antenna or counterpoise lead-in into the build- 
ing, a tube or bushing of non-absorptive insulating material shall be 
used and shall be installed so as to have a creepage and air-gap dis- 
tance of at least five (5) inches to any extraneous body. If porcelain 
or other fragile material is used, it shall be installed so as to be pro- 
tected from mechanical injury. A drilled window pane may be used 
in place of bushing, provided five (5) inch creepage and air-gap 
distance is maintained. 

PROTECTIVE GROUNDING SWITCH 

(j) A double-throw knife switch having a break distance of 
four (4) inches and a blade not less than one-eighth (%) inch by one- 
half (%) inch shall be used to join the antenna and counterpoise 
lead-ins to the ground conductor. The switch may be located inside or 
outside the building. The base of the switch shall be of non- 
absorptive insulating material. Slate base switches are not recom- 
mended. This switch must be so mounted that its current-carrying 
parts will be at least five (5) inches clear of the building wall or 
other conductors and located preferably in the most direct line be- 
tween the lead-in conductors and the point where ground connection 
is made. The conductor from grounding switch to ground connection 
must be seciirely supported. 

PROTECTIVE GROUND WIRE 

(k) Antenna and counterpoise conductors must be effectively and 
permanently grounded at all times when station is not in actual oper- 
ation (unattended) by a conductor at least as large as the lead-in, 
and in no case shall it be smaller than No. 14 B. & S. gage copper or 
approved copper-clad steel. This ground wire need not be insulated 
or mounted on insulating supports. The ground wire shall be run in 
as straight a line as possible to a good permanent ground. Preference 
shall be given to water piping. Gas piping shall not be used for the 
ground connection. Other permissible grounds are the grounded steel 
frames of buildings and other grounded metal work in buildings and 
artificial grounding devices such as driven pipes, plates, cones, etc. 
The ground wire shall be protected against mechanical injury. An 
approved ground clamp shall be used wherever the ground wire is 
connected to pipes or piping. 



144 RADIO FOR ALL 

OPERATING GROUND WIRE 

(1) The radio operating ground conductor shall be of copper strip 
not less than three-eighths (%) inch wide by one-sixty-fourth (1/64,) 
inch thick, or of copper or approved copper-clad steel having a peri- 
phery, or girth (around the outside) of at least three-quarters (%) 
inch (for example a No. 2 B. & S. gage wire), and shall be firmly 
secured in place throughout its length. The radio operating ground 
conductor shall be protected and supported similar to the lead- 
in conductors. 

OPERATING GROUND 

(m) The operating ground conductor shall be connected to a good 
permanent ground. Preference shall be given to water piping. Gas 
piping shall not be used for ground connections. Other permissible 
grounds are grounded steel frames of buildings or other grounded 
metal work in the building and artificial grounding devices such as 
driven pipes, plates, cones, etc. 

POWER FROM STREET MAINS 
(n) When the current supply is obtained directly from street 

mains, the circuit shall be installed in approved metal conduit, armored 

cable or metal raceways. 

If lead covered wire is used, it shall be protected throughout its 

length in approved metal conduit or metal raceways. 

PROTECTION FROM SURGES, ETC. 

(o) In order to protect the supply system from high-potential 
surges and kick-backs, there must be installed in the supply line as 
near as possible to each radio-transformer, rotary spark gap, motor- 
generator sets and other auxiliary apparatus one of the following: 

1. Two condensers (each of not less than one-half (%) microfarad 
capacity and capable of withstanding six hundred (600 volt test) in 
series across the line and mid-point between condensers grounded; 
across (in parallel with) each of these condensers shall be connected 
a shunting fixed spark gap capable of not more than one-thirty-second 
(1/32) inch separation. 

2. Two vacuum tube type protectors in series across the line with 
the mid-point grounded. 

3. Non-inductively wound resistors connected across the line with 
mid-point grounded. 

4. Electrolytic lightning arresters such as the aluminum cell type. 
In no case shall the ground wire of surge and kick-back pro- 



AERIALS, LOOP TRIALS, GROUNDS 145 

tective devices be run in parallel with the operating ground wire when 
within a distance of thirty (30) feet 

The ground wire of the surge and kick-back protective devices 
shall not be connected to the operating ground or ground wire. 

SUITABLE DEVICES 

(p) Transformers, voltage reducers, keys, and other devices em- 
ployed shall be of types suitable for radio operation. 

These rules do not apply to radio equipment installed on ship- 
board, but have been prepared with reference to land stations. 

RECEIVING EQUIPMENT 

(a) Antenna Indoor receiving antennae are not included within 
the requirements of this proposed rule, which provides for the pro- 
tection of radio equipment against lightning. Indoor receiving 
antennae and auxiliary apparatus are, however, included in the general 
requirements covering the wiring of signal systems, for it is obviously 
desirable to insure, for example, the freedom of all receiving apparatus 
from contact with electrical power circuits either inside or outside 
of buildings. 

It is desirable that electrical construction companies install radio 
antennae and apparatus for persons who are not familiar with electric 
wiring. This will tend to insure the installation of antennae and 
apparatus in a strong and durable manner. It is important that an- 
tenna wire be used in such size and tensile strength as to avoid its 
coming in contact with any electric power wires whatsoever. 

The size and material of which the antenna is made should depend, 
to some extent, upon the length of the span which the antenna must 
bridge. It is suggested that for the ordinary receiving antenna about 
100 feet long No. 14 B. & S. gage soft drawn copper wire can safely 
be used. If other materials are used, the size which is chosen should 
be such as to insure tensile strength at least equal to that of the 
No. 14 soft copper wire suggested above. 

The requirements covering splices and joints in the antenna span 
are for the purposes of avoiding accidental falling of such wires upon 
light and power wires, of less than 600 volts where it is found neces- 
sary to cross such lines. The rules, it will be noted, permit crossings 
with lines of 600 volts or less, if they do not happen to be trolley 
wires or feeders to trolley wires. In such a case, it is desirable to use 
wire of a larger size than 14 B. & S. gage in order to minimize the 
chance of accidental contact of the antenna with the power wires. 

The interchangeable use of copper and of approved copper-clad 
conductor is suggested on account of the fact that these two kinds of 
10 



146 RADIO FOR ALL 

wire are practically equivalent in their conductivity for high- 
frequency current. 

(b) Lead-in Wires No mention is made of the insulation from the 
building of the receiving antenna or lead-in wire except that this 
lead-in wire should be run through a bushing. The latter provision 
is chiefly to protect the wiring against the possibility of short- 
circuiting with electric power lines which may run in the wall and 
whose location may be unknown to the persons installing the radio 
equipment. This requirement serves also to protect the antenna lead- 
in wire against contact with metal lath or other metal parts of 
the building. 

From a signaling standpoint, it is desirable to use insulators for 
receiving antennae in order that wet weather may not cause the an- 
tenna to become partly short-circuited to the ground. 

(c) Protective Device The requirement for a protective device 
to be connected between the antenna and ground terminals of the re- 
ceiving set is for the purpose of carrying lightning discharges or less 
violent discharges caused by induction or by atmospheric electricity 
to the ground with a minimum chance of damage to the receiving 
apparatus, building, or operator. A fuse is not required as a part 
of the protective device, though lightning arresters which are provided 
with fuses will not necessarily fail to receive approval. If a fused 
lightning arrester is used, it makes it less likely that the antenna 
terminals of a receiving set will be put in a high voltage in case the 
antenna falls upon an electric light or power wire. The absence of 
the fuse, on the other hand, makes it possible for the antenna, if it 
accidentally falls across the power wires, to become fused at the point 
of contact and thus fall to the ground and eliminate the hazard. The 
antenna terminal of the receiving set should be connected to the point 
of junction of the fuse with the arrester. 

Lightning arresters may be used inside the building, and in such a 
case they will receive better protection from moisture and mechanical 
injury than lightning arresters placed on the outside of a build- 
ing wall. 

Protective devices of reliable manufacture are approved by the 
Underwriters' Laboratories, and can be depended upon to operate at 
the required voltage. The use of a cheaply constructed home-made 
arrester is not recommended, since it may easily get out of order and 
fail to operate at the low voltage which is desirable. Arresters should 
be inclosed in such a way as to protect the breakdown gap from dust 
One disadvantage of the vacuum tube type of arrester is that it may 
cease to function without giving warning that it is inoperative. A 



AERIALS, LOOP AERIALS, GROUNDS 147 

list of the approved protective devices and ground clamps is contained 
in the "List of Inspected Electrical Appliances," published by the 
Underwriters' Laboratories. This list is revised semi-annually and 
may be consulted upon application to the principal office of the Under- 
writers' Laboratories, Inc., 207 East Ohio St., Chicago, 111., and at 
offices and agencies throughout the United States and Canada. 

While an arrester connected between the antenna and ground is 
regarded by many as sufficient protection, it is somewhat safer to in- 
stall a switch in parallel with it as an added protection. Particularly 
if the arrester is inside of the building and the ground connection is 
made to a radiator, it is desirable to use in addition the outside 
ground connection. 

If the antenna is properly connected to the ground, such connec- 
tion prevents the antenna from becoming a hazard to the building and 
its contents and may act to supplement the protection given by 
lightning rods. The arrester should have the most direct connection to 
the ground which it is feasible to make, otherwise the antenna may be- 
come a hazard with respect to lightning. 

(d) Protective Ground Wire While it is desirable to run the pro- 
tective ground wire in as direct a line to ground as possible, it is 
more important to provide a satisfactory contact at the ground itself 
than to avoid a few bends in the ground wire. 

(f) Receiving Equipment Ground Wire If the ground wire of a 
receiving set passes through a wall it should be insulated for the same 
reasons as the antenna lead-in wire referred to in paragraph 
(a) above. 

If the ground wire is exposed at all to mechanical injury it should 
be of larger size than the minimum permitted under the rules and 
certainly not smaller than No. 10 B. & S. gage. It should, for mechani- 
cal protection, be enclosed in wood moulding or other insulating 
material. Ground wires should not be run through iron pipe or con- 
duit because of the choking effect at radio and lightning frequencies. 

TRANSMITTING EQUIPMENT 

(j) Protective Ground Switch On account of the larger size of 
the ordinary transmitting antenna, it is more likely to be subject to 
damage from lightning; and on account of the high voltages produced 
by radio transmitting equipment, it is desirable to provide for the 
use of a double-throw switch for connecting the antenna either to the 
transmitting apparatus or to the ground. The use of this switch 
makes it possible to entirely disconnect the antenna from the trans- 
mitting apparatus when not in use. 



148 RADIO FOR ALL 

The objection to slate-base switches is chiefly from the radio 
engineering viewpoint, on account of the absorption of water by 
many kinds of slate and the presence of conducting streaks. 

Under this rule one has the choice of the standard 100-ampere 
600-volt single-pole, double throw switch or a special antenna switch 
using 60-ampere copper which has an air-gap distance of at least 
four inches. 

(o) Protection from Surges, etc. On account of the difficulty 
which has been experienced by the induction of voltages in the supply 
lines of a transmitting station, it is advisable to use a protective 
device across the terminals of each machine or transformer connected 
to this power line. It would also seem desirable to connect a similar 
protective device across the power line and near the point of its 
entrance to the building and on the house side of the meters. 

It is desirable that research on the performance of protective de- 
vices and the means of avoiding surges and " kick-backs " in the power 
supply lines be promoted. 

For further suggestions regarding good and bad practice in the 
installation and maintenance of signal wires and equipment, reference 
should be made to "National Electrical Safety Code, 3rd Edition, 
October 31, 1920, Bureau of Standards Handbook No. 3 " and espe- 
cially Section 39. This is obtainable from the Superintendent of 
Documents, Government Printing Office, Washington, D. C. 

The 1920 edition of the " National Electrical Code," which contains 
the regulations of the National Board of Fire Underwriters, includ- 
ing Rule 86, which is now the rule in effect covering radio signaling 
apparatus, may be referred to at any local inspection department of 
the fire underwriters, or may be purchased from the National Board 
of Fire Underwriters, 76 William St., New York City. 




Mme. Olga Petrova, famous actress, authoress of the play "White Peacock" recently entertained 
through WJZ, the Westinghouse Radio Corp. Broadcasting Station at 
Newark, by si _' _ 
next day she received 968 very complimentary letters from the invisible audience. 



her largest audience 

Newark, by singing several songs and telling stories about her _stage and screen su 



the 



CHAPTER VIII 

RADIO DIAGRAMS AND HOW TO 
READ THEM 

HERETOFORE in our illustrations we have shown 
perspective views of all the instruments and how 
they are wired together, etc. As the reader becomes 
more familiar with radio matters, he should take 
up the study of diagrams because a glance at one 
will show the connections. A radio diagram is to 
a perspective drawing what stenography is to long 
hand. Radio diagrams give us the means to tell 
at a glance what the connections of the various in- 
struments are, and as a matter of fact it is much 
simpler to read a diagram than a perspective draw- 
ing. It is much harder to read a perspective draw- 
ing than a diagram because in the former, such as 
we have shown heretofore, there is nothing but a 
maze of wires, one crossing the other, and one really 
never knows where one is. The diagram on the 
other hand simplifies matters a great deal and it 
becomes a comparatively easy matter to trace a cir- 
cuit by means of the diagram. Certain symbols 
are used to describe apparatus and in our illustra- 
tions 80 to 85, we have shown the various symbols 
graphically. By studying these symbols and mem- 
orizing them, it becomes a simple matter to trace the 
various circuits and study the diagrams. 

Diagrams and circuits form a great chapter by 
themselves, and it is not within the range of this 

149 



150 



RADIO FOR ALL 




MfEMMTOR 



OR 



B-BATTERY 



J.I.LI.I 1 I 

1 1 ! II II 



AMMETER 



OR 



BUZZER 




JIERML 



FIXED 
CONDENSER 



Hh 



100PAERML 



V/M/1BLE 
CONDENSER 



A-BATTERY 



CONNECT/ON 



FIG. 80-81. 



book to cover all points, because a number of books 
could be obtained on vacuum tube diagrams alone, 
and for this reason we will not go deeply into the 



RADIO DIAGRAMS, HOW TO READ THEM 151 



NOCOMCT/OH 



I 



SMW&tP 



-00- 



CO/L 



TVMN6 CO/L 

V/IK/0BLE 

INDUCTANCE 



GROUND 



COUPLED COHS 

WITH V/?#W 

BL COUPLING 



KEY 



DETECTOR 
(CRYSTAL) 



RESISTANCE 



matter. Suffice it to say that the diagrams which 
are shown on the following pages all have a reason 
for being, and all are the outcome of many thou- 



152 



RADIO FOR ALL 



VARIABLE 
RESISTANCE 



CHOKECOIL 



SW/TCH 



WWN7UK 



TELEPHONE 
RECEIVER 



VOLTMETER 



TRANSMITTER 



VARIOMETER 



WR/OCOUPUR 



TRANSFORMER. 



DYNAMO 
ORMOTOR 



sands of experiments. The diagrams shown have 
been selected and in order that the reader may fam- 
iliarize himself with them, the captions under the 



RADIO DIAGRAMS, HOW TO READ THEM 153 

diagrams show to which perspective drawing in 
the front of the book they refer. The diagram of 




Hflii- 



FIG. 86. REFER TO Fio. 7. 




Fro. 87. REFER TO Fio. 10. 



the perspective drawing, therefore, may be com- 
pared and the circuits traced. The reader should 
take a pad and paper and trace a few diagrams 



154 



RADIO FOR ALL 



himself in order to become acquainted with the va- 
rious circuits. It should be understood, of course, 
that not all connections that the reader will think 




Fro. 88. REFEB TO FIQ. 18. 



Fio. 89. Buna TO FIG. 19. 



of will work. There are certain fundamentals in 
radio which must be observed, and there are reasons 
for them all. For instance, it makes a great differ- 
ence in what part of the circuit the crystal detector 



RADIO DIAGRAMS, HOW TO READ THEM 155 





Fio. 90. REFEB TO Fio. 22. 








Fio. 91. REFEB TO Fio. 



or telephone is placed. All these points have been 
studied in the past and certain definite results have 



156 



RADIO FOR ALL 





FIG. 93. REFEB TO Fia. S3.' 

been achieved. Of course, the reader is encouraged 
to experiment in his own way by connecting his in- 
struments in various combinations, which are almost 



RADIO DIAGRAMS, HOW TO READ THEM 157 





Fio. 96. REFEB TO Flo. 87. 



endless, but he will find that the diagrams as we 
show them here will work best as a general rule. 
The study of radio diagrams is not difficult at 



158 



RADIO FOB ALL 




Fio. 96. REFEB TO FIG. 47. 




FIG. 97. REFEB TO Fio. St. 



all, once the fundamentals are clearly understood, 
but it is necessary to first memorize symbols, other- 
wise not much headway will be made. 

For the guidance of the reader, we would first 
advise memorizing the following: "asrial, ground, 



RADIO DIAGRAMS, HOW TO READ THEM 159 

detector, phones." These are the simplest and es- 
sential ones, and for that reason, we have shown 




To instruments-^ 



Fio. 08. RBFBB TO Fio. 66. 




V.C. 



To-" 

instruments 



these first in our diagrams. Once the various con- 
nections have been mastered, it then becomes a sim- 
ple matter to go ahead with the others. 

Of course, where the reader is becoming suffi- 
ciently interested in radio to be a radio experimen- 



160 



RADIO FOR ALL 




To. .instruments 



Fro. 100. BKTKB TO Flo. 50. 




TC. 



To instruments *- 




Fio. 101. Ricnta TO Fia. 60. 



ter, the study of diagrams will not long remain fas- 
cinating. He will wish to make the actual connec- 
tions on the instruments himself, and we greatly 



RADIO DIAGRAMS, HOW TO READ THEM 161 




Vorio- coupler Grid leaK 

ri nto ( rvond cond. 



Audi 

-U 
r Rheostat - 

Enable 
condenser 




/A' battery. 



B' battery 



Fio. 102. RJCFEB TO Fia. 72. 



Aerial- 



Direct current, generator 



L Tuning 
" 



Ghoke coils 

I 



Grxwnd 



P 



converter 
Microphone 



Fia. 103. RKFEB TO Fio. 106. 



encourage this, and assure every reader that he 
will derive more information and satisfaction from 
actual connections than from anything else in radio. 
11 



162 



RADIO FOR ALL 



Aerial 



Grid leaK and condenser 




Variable t(S Microphone 
condenser 



Hiqh tension 
D.C. Source 



FIQ. 104. RETEB TO Fia. 108. 



Voice 
amplifier 
Microphone \ Modulator 




To generator 



FIG. 105. RKFEB TO Fro. 100. 



RADIO DIAGRAMS, HOW TO READ THEM 163 

In connection with these diagrams, as mentioned 
before, in order that the reader may better study 
them, we have listed only such diagrams, the per- 
spective drawings of which have been shown in other 
sections of the book. 

Thus the diagram shown in Fig. 86 is shown in 
perspective in Fig. 7, Fig. 87 refers to Fig. 10, Fig. 
88 refers to Fig. 18, Fig. 89 refers to Fig. 19, Fig. 
90 refers to Fig. 22, Fig. 91 refers to Fig. 26, Fig. 
92 refers to Fig. 31, Fig. 93 refers to Fig. 33, Fig. 
94 refers to Fig. 34, Fig. 95 refers to Fig. 37, Fig. 
96 refers to Fig. 47, Fig. 97 refers to Fig. 52, Fig. 
98 refers to Fig. 56, Fig. 99 refers to Fig. 57, Fig. 
100 refers to Fig. 59, Fig. 101 refers to Fig. 60, Fig. 
102 refers to Fig. 72, Fig. 103 refers to Fig. 106; 
Fig. 104 refers to Fig. 108, Fig. 105 refers to 
Fig. 109. 

It is not the purpose of this book to be of such 
a technical nature as to list several hundred dia- 
grams, as there are other books making a specialty 
of this. The purpose of the few diagrams is merely 
to acquaint the reader with the first principles. 



CHAPTER IX 
RADIO TELEPHONY 

We have already mentioned radio telephony 
in previous chapters, but not insofar as the trans- 
mitting is concerned. We have already learned 
that radio telephony is not a new art, but has been 
known for many years. The first to send radio tele- 



Tuning coil T 



To direct current generator 
Choke coils 




Arc converter 



\J I OU I IU ..!.:: .-..-.-.: .v.v-.-J T.-Vr'.' 





Fra. 106. 

phone messages over long distances was Valdemar 
Poulsen. The important instrument which he used 
in his experiments was the electric arc. The dia- 
gram of connections is shown in Fig. 106. It was 
found that with a suitable arrangement the electric 
arc became capable of sending out undamped waves 
which are also known under the definition of contin- 
uous waves. In other words, the electric arc sends 
out a wave that is continuous without interruption. 

164 




Radio 

Mme. Johanna Gadski, famous operatic soprano, singing Wagner's "Elizabeth's Aria from Tann- 
hauser" through WJZ to the radio telephone audience. Mme. Gadski began her musical educa- 
tion at the age of seven, had her first public appearance at ten, made her debut in opera at the 
age of sixteen, and later enjoyed a continuous engagement for twenty-three consecutiv 
with the Metropolitan Opera Co. of New York. 



RADIO TELEPHONY 



165 



We have learned something about continuous waves 
in a former chapter. Such an arc transmitter, 
therefore, sends out waves that never stop, not even 
for the smallest fraction of a second. By means of 
the microphone into which we talk, we super-impose 
upon the continuous waves the voice currents which 
are, therefore, carried along by those waves. 
Hence, the continuous wave in radio telephony is 



Voice current 
(Audio frequency) 




Radio frequency 



FIG. 107. 

often spoken of as the carrier wave, because it car- 
ries the speech waves with it. This is shown in Fig. 
107, schematically where the speech waves will be 
seen carried along with the continuous waves, which 
are emanating from the oscillating circuit. 

The advent of the vacuum tube changed the en- 
tire aspect of radio telephony. In the Poulsen 
method as well as for radio telephone systems, it 
was necessary to employ a microphone, which in 
this case had to handle very large currents, some- 
times as high as ten amperes. It was almost impos- 
sible to design a microphone or transmitter that 
would absorb such an excessive amount of energy, 



166 RADIO FOR ALL 

and for that reason the modulation at the transmit- 
ting station was nearly always faulty, and the re- 
ceived speech, music or other entertainment was as 
a rule poor. Often the microphone failed to 
work, and then, of course nothing came through 
the air at all. At the present time, however, we are 
not dependent upon power microphones, for the 




FIG. 1C8. 

reason that we now make use of the vacuum tube. 
Even the simplest telephone transmitter such as 
used on your house telephone can be used in the 
modern radio telephone, and the main reason is that 
the vacuum tube sender acts as a valve, which ampli- 
fies many thousand times the voice current, sending 
it out over the aerial without having a strong current 
passing through the microphone. 

The simplest radio telephone is shown in Fig. 
108. This comprises a transmitter, a few batteries, 
a vacuum tube and the usual serial and ground. The 



RADIO TELEPHONY 167 

diagram is shown fully in our illustration, Fig. 104. 
By means of this arrangement, when we talk into 
the transmitter, the oscillations generated by the va- 
cuum tube are varied in amplitude. These high 
frequency radio currents are continuous as well, so 
that we are sending out or transmitting a continuous 
wave. When words are now spoken into the trans- 
mitter the voice currents are superimposed upon 
the continuous waves, and at the receiving station, 
the words will be heard. The outfit, as shown in 
this illustration, is of course, only good for a short 
range because not much power is used, and it will, 
therefore, not cover more than a few miles. The 
principle, however, is the same as that used in our 
large broadcasting station, as we will see further on. 

The system which we have just explained is the 
one which is used universally today, as it has been 
found that by the use of the vacuum tubes almost 
any amount of power can be radiated from the trans- 
mitting antenna. Usually a radio telephone sta- 
tion is rated according to the amount of power it 
radiates from its transmitting serial. This amount 
of power, of course, varies for the different stations. 
The more power we put into the serial, the further 
we can transmit. 

The prime reason why we can hear spark sta- 
tions much further than radio telephone stations, 
lies in the reason that in the former many kilowatts 
are used, sometimes as high as a thousand kilowatts, 
as for instance, in the great trans- Atlantic stations. 



168 RADIO FOR ALL 

Of course, not all this power leaves the serial, but 
a fair proportion of it does. In radio telephony, 
however, not such a vast amount of energy is used, 
and most broadcasting stations do not operate on 
more than 500 watts, which, compared to a spark 
station is an insignificant amount of power. This 
is one of the reasons why broadcasting stations 
cannot be heard at such great distances as 
spark stations. 

BROADCASTING 

Radio broadcasting, contrary to public opinion, 
is not at all a new thing. Many claims are being 
made as to who was the original inventor of broad- 
casting, and when everything is said and done, it 
probably settles down to the man who sent out the 
first radio telephone intelligence. That man was 
probably Reginald Fessenden, who, as far as is 
known was the first and real inventor of radio tele- 
phony. Back in 1906, he operated a radio tele- 
phone transmitting station which was heard by thou- 
sands of radio professionals as well as amateurs. 
That advent marked the first broadcasting. Of 
course, this was not broadcasting as we understand 
the term today. By modern broadcasting is under- 
stood a radio intelligence that is sent out at a certain 
pre-determined schedule or program. Such broad- 
casting probably did not come about until 1920. 
when the Westinghouse Company transmitted the 
1920 election returns from the East Pittsburgh sta- 
tion, and followed this with daily concerts and other 



RADIO TELEPHONY 169 

entertainment which has remained to this day. 
The country at large, however, did not become much 
interested until the latter part of 1921, when the 
Newark, N. J. Westinghouse station began to 
broadcast a daily program. The newspapers were 
not slow in taking up the new art, and one of 
Newark's leading newspapers was the first of the 
newspapers in the country to have a regular radio 
section in their Sunday edition. This attracted 
many readers, who before had not known much 
about radio, and to whom radio had been a 
sealed book. 

Newark, N. J. became the first radio center of 
the country, and soon people were storming the elec- 
trical and radio supply stores in order to buy instru- 
ments with which to receive radio entertainments. 
New York soon followed suit, the New York Globe 
being the first daily newspaper to carry a daily radio 
department, informing the public as to the wonders 
of radio, and how it was possible for everyone to 
catch music from the air at a trifling cost. Soon 
other New York papers copied the idea, and in less 
than a month, there was hardly a city in the United 
States within fifty miles of a broadcasting stations 
that did not boast of its radio page or department. 
All this tremendous publicity had its effect upon 
the public who began to storm the stores and clamor 
for radio goods until in January and February, 
1922, the radio boom had reached a situation that 
can only be compared to the oil rush of the Texas 



170 RADIO FOR ALL 

oil fields. The country had suddenly gone wild 
over radio, and every one wanted to have an outfit to 
listen in to the fascinating entertainment. 

So far for the history of broadcasting. Tech- 
nically, the art of broadcasting was partially de- 




A- Microphone; B- Dry cells ; C- Audio frequency amplifying 
transformer; D- ChoKe coil; E- Radio frequency choke coil; 
F- Tuning inductance; G- Voice amplifier; H- Modulator, J- 
Oscillator; K- Grid condenser ;*L- Variable condenser; M- 
Grid leaK; N- Plate battery; 0- Storage battery;. 



FIG. 109. 

scribed in the preceding chapter. At the modern 
broadcasting station, the arrangement as shown in 
Fig. 109 is made use of. Here, we first have the 
microphone into which the performer sings or 
speaks, and a small transformer to step up voice 
currents. Next, we have the voice amplifier where 
the voice currents are stepped up and from thence 



RADIO TELEPHONY 171 

pass into a second transformer. From there the 
currents pass through the so-called modulator tube, 
and from there through several coils into the next 
tube called the oscillator. Then the current passes 
out into the antenna circuit. Of course, all this is 
much more complicated, and it is not within the 
limits of this volume to delve into all the technical- 
ities of this circuit. Suffice it to say that by means 
of this arrangement, almost any amount of energy 
may be radiated out into space. 

Of course, it goes without saying that the trans- 
mitting tubes used for transmitting broadcast 
entertainment are not the small vacuum tubes with 
which we are familiar, because these could not han- 
dle the energy. Instead, the tubes used are big 
fellows, a foot or so high and 6 to 10 inches in dia- 
meter. Such tubes of which an entire battery is 
used, are built to carry large amounts of current, 
and as a result become pretty hot. For that rea- 
son, they are cooled by means of fans or other cir- 
culating air methods. Even so the tubes do not 
last forever, and occasionally burn out. If this 
happens in the midst of an entertainment, which is 
unfortunate, a new tube must be replaced and the 
performer as a rule must go over the ground again, 
after the radio audience has been informed of 
the blow-out. 

At the broadcasting station, it is always neces- 
sary to have a complete personnel which often com- 
prises as many as twenty people. There are two 



in RADIO FOR ALL 

distinct parts in the up-to-date broadcasting sta- 
tion. First, the studio, and second the transmit- 
ting station proper. At the latter we have several 
engineers who attend to the operation of the tubes, 
and who are informed by telephone from the studio, 
whenever the artist is ready to sing or perform. The 
current is then switched on, the tubes begin to glow 
and the station now transmits continuous waves. 
These continuous waves cannot be heard at the re- 
ceiving station, except at times, when we employ a 
regenerative receiver. As soon as this receiver 
gives its characteristic whistling note, we can tell 
the broadcasting station has started its power, al- 
though the performance has not begun. 

Let us now enter the broadcasting station studio. 
We assume that an opera singer is getting ready to 
sing, while the accompanist is at the piano. The 
attendant first announces the singer, and cautions 
the performers not to make any noise whatsoever, 
because any unnecessary noises such as coughing or 
talking, will be heard by the radio audience. These 
sounds are picked up by the sensitive transmitter. 
In order to dim the echoes in the studio, its walls 
are always covered with draperies which do away 
with all sound reflections, echoes and the like. After 
the introduction by the announcer, the performer 
steps up to the transmitter, which is usually a form 
of telephone transmitter attached to a large vibrat- 
ing disc and looks somewhat like a small bowl. The 
performer is cautioned never to stand nearer than a 



RADIO TELEPHONY 173 

foot or so before the transmitter when singing. 
Behind the piano there is usually some sort of horn 
which picks up the sounds and conveys them to a 
microphone attached to the small opening of the 
horn. This catches the sounds from the piano, to be 
sent to the transmitting station. Of course, the 
microphone transmitter wires coming from the 
piano as well as those from the performer are con- 
nected together, so that the sounds are picked up 
simultaneously and guided to the radio transmitter. 
That is why in the receiver we hear the piano and 
performer's voice at the same time. To be sure, 
there are certain refinements at every broadcasting 
station in order to transmit the music or other enter- 
tainment best. 

Several microphones are used, for instance, when 
a band is playing. A totally different arrangement 
is used when a violinist is performing. In the latter 
case a very sensitive microphonic arrangement must 
be used, otherwise we would hear nothing of the 
music, which is not unduly loud anyway. On the 
other hand, when phonographic music is transmit- 
ted, there is a phonograph-microphone attachment, 
which is attached direct to the tone-arm of the 
phonograph, and we, therefore, hear transmitted 
phonograph music, the same as if we were in the 
room with the phonograph. 

Several of our photographic illustrations shown 
in this book depict the various methods used 



174 RADIO FOB, ALL 

in broadcasting music from a modern broad- 
casting station. 

We are of course only at the beginning of broad- 
casting. What its future will be is difficult to state, 
as is always the case with a new art. 

At the present time there is a distinct and very 
important use for broadcasted entertainment. A 
broadcasting station now-a-days sends out news, 
music, which may be vocal, instrumental, or any 
other form. We also have stock quotations, 
weather forecasts, children's stories, lectures and 
even complete musical shows or operas have been 
broadcasted lately. Entire vaudeville programs that 
lend themselves to the purpose can thus be broad- 
casted. A distinct field of usefulness lies in the 
possibility of the radio telephone for political 
speeches. There is talk at Washington at the pres- 
ent time that Congress will install a powerful broad- 
casting station at the Capitol whereby the President 
or other politicians may broadcast their speeches so 
that every one in the country may hear. This is 
a tremendous possibility. 

Then we have perhaps a more important feature 
of broadcasting, and that is educational programs. 
The day is not far off when every university will 
have its broadcasting station whereby special 
courses that lend themselves for the purpose will be 
broadcasted so that everyone who cares to may hear 
and absorb the knowledge given by our professors. 

One of the surprising uses of broadcasting is that 



RADIO TELEPHONY 175 

it is possible today to make actual phonograph re- 
cords from broadcasted music. There are now on the 
market attachments which can be placed upon your 
phonograph. Then by attaching a loud talking re- 
ceiver to the tone-arm, it is possible to take down any 
form of entertainment on a wax or zinc disc, which 
can be put away for future use. Imagine that a 
great opera singer is sending out one of her arias 
right at the opera during a regular performance. 
All we have to do is to record her voice, thereby 
making our own phonograph records, and this to- 
day may be done without any further trouble. Then 
if we wish to hear the artist again, all we have to do 
is to place our wax or zinc record upon the turning 
table, and we can listen to the artist at will a month 
or a year later. 

It is even possible today to have an entire opera 
broadcasted, moving pictures and radio music, all 
at the same time. This scheme was originated by 
the author in 1919 and is as follows: ( See Fig. 110.) 

A recent newspaper report from Chicago brought the not at all 
surprising news that grand opera music had been transmitted by 
wireless telephone for over one hundred miles. Sensitive microphones 
placed on the stage of the opera house caught the sound waves; the 
impulses then being stepped up in the usual manner by means of a 
transformer were led into an amplifying vacuum tube. Here the cur- 
rent was impressed upon the radio telephone transmitter in successive 
stages and then sent out over the aerial on top of the opera house. 
Wireless amateurs all about the surrounding country were thus able 
for the first time to hear grand opera. While this was only an experi- 
ment, grand opera by wireless will soon be an accomplished fact. 

During the next few years it will be a common enough experience 
for an amateur to pick up his receivers between eight and eleven 
o'clock in the evening and listen not only to the voice of such stars as 



176 RADIO TELEPHONY 

Scotti, Tetrazzini, Mac Cormick and others, but also to the orchestra 
music as well, which is picked up by the sensitive transmitter along 
with the voices of the stars. The surprising thing is that it is not 
being done now. 

This probably is due to the fact that as yet no means has 
been found to reimburse the opera companies for allowing everyone to 
listen in. While of course listening to the music is not as satisfying 
as witnessing the performance in person, still many music enthusiasts 
would rather stay home listening to the music alone than to witness 
the performance itself. To your true, dyed-in-the-wool opera fiend 
the performance is of secondary importance, the music always 
coming first. 

But we must give a thought to the management, which cannot sub- 
sist on an empty opera house if everyone could listen in to the actual 
rendering of the opera without paying for the privilege. Needless to 
say that the producers would soon find themselves bankrupt. For this 
reason we cannot expect that grand opera by wireless will be an accom- 
plished fact until some means has been found to reimburse the pro- 
ducers, and, as every wireless man knows, this is very difficult to do. 
Anyone with suitable radio apparatus can "listen in" to the music 
without much trouble. No matter on what wave-length the music 
would be rendered, every wireless man would find a way to listen to 
it without serious inconvenience. 

Probably the only logical way out would be for the management 
of a grand opera company to advertise in the newspapers, stating that 
no grand opera via radio would be given unless a certain amount of 
revenue were guaranteed by radio subscribers before " radio per- 
formances" would be given. This would mean that probably ten 
out of one hundred radio stations, amateurs and otherwise would pay 
monthly or yearly dues to sustain the management, which then would 
not have to care how many were listening in. 

This is the only practical solution. As for technical difficulties, 
there are of course none. All that is necessary for the producing 
company is to install a high-class wireless telephone outfit which can 
be bought on the market right now and which is immediately available. 
The rest is up to the wireless fraternity, which has nothing else to do 
but listen in. 

At the receiving end, the future up-to-date radio opera enthusiast 
will of course, have a first-class receiving outfit, using vacuum tube 
amplifiers, and a loud talker. Then it will be a simple matter to 
listen to Scotti himself, though he be a thousand miles distant. His 
voice will come out loud and distinct and the amateur's family will be 
enabled to " listen in " to their heart's content. 



RADIO FOR ALL 177 

There is still another novel scheme recently originated by 
the writer. 

The underlying idea is not only to give grand opera by wireless, 
listen to the music and to the singers only, but to actually tee the 
operatic stars on the screen as well. This is how it can be readily 
accomplished by means which are available to-day, and without the 
slightest technical difficulty. 

Let us say, by way of example, that the opera " Aida " is filmed 
in its entirety. This may mean a four or five reel feature. The opera 
will be filmed just like any other photo-play. 

Our large illustration shows what happens next. The stars, sing- 
ers, players, the chorus, orchestra, conductor, etc., are then assembled 
in a moving picture studio and in front of them is the usual screen. 
The opera " Aida," which had been filmed before, t* now repeated on 
the screen while the entire cast follows the screen picture closely. 
Each performer, every star, every member of the chorus has his or 
her own microphone in which he or she sings the regular score, watch- 
ing closely the film-play as the action is unreeled on the screen. The 
moving picture opera through the film operator keeps time with the 
singers, and the singers themselves must keep exact time with the 
performance as it is unrolled on the screen before their eyes. Inas- 
much as the identical cast has been filmed, it will not be difficult for 
them to keep time with their own performance, as may readily be 
imagined. In other words, when Scotti sees his own figure appearing 
on the screen he will know exactly how and when to sing into the 
microphone in front of him. 

All of the microphones go to the wireless telephone station located 
in the radio room above, and there are, of course, sensitive microphones 
in the studio which pick up the sounds from the orchestra as well. 
All sounds are then stepped up through the usual amplifiers and are 
then fed into the high power vacuum pliotrons, which finally amplify 
the original sound several million times. These impulses are then sent 
out over the usual aerial located on top of the house and are shot out 
all over the country instantaneously. 

Five hundred to 1,000 miles away and for that matter all over the 
country every moving picture house will have been supplied with 
the identical film at the stated performance, it having been announced 
days ahead that the grand opera "Aida" will be given at such and 
such an hour. 

Of course, where the distances are large, the hour of rendering the 
opera will vary. Thus, for instance, if Scotti were singing in New 
York and a performance would start at eight o'clock in the evening, 
12 



178 



RADIO FOR ALL 




RADIO TELEPHONY 179 

New York time, it would start in San Francisco at four o'clock in the 
afternoon, as a matinee, due to the difference of time. Inasmuch as 
such performance would probably only be held once a month, people 
would not mind the inconvenience due to slight difference of time. 

Every moving picture house will have its receiving apparatus with 
its usual amplifiers and anywhere from six to one dozen loud talkers 
scattered through the house. Exactly at the stated time the moving 
picture operator will begin grinding away the opera has begun. 
Simultaneously the distant orchestra will begin playing, filling the 
house with music. 

When the actual performance begins, it will be an easy matter for 
the operator to keep time with the incoming music. All he needs to do 
is to grind faster or slower, and inasmuch as Scotti with his per- 
formers in New York is watching the identical film, the distant oper- 
ator will have no trouble in having the music keep time with his 
film. If he finds that he runs ahead for one second, he can readily 
slow up the next and vice versa. With a little practice it will be easy 
for the distant operator to time himself perfectly, thus giving the 
patrons of his house an ideal performance. 

From a financial standpoint it would be good business for the opera 
company, as well as for the moving picture house, both of which would 
thus derive a new income running into the hundreds of thousands with 
hardly any expense whatsoever. The grand opera with an outlay 
of from one thousand to three thousand dollars could buy its high 
power radio telephone outfit, while every live picture house through- 
out the country would be able with an expenditure of less than five 
hundred dollars to buy its necessary radio telephone equipment and 
this cost would only be initial, because nothing except burnt-out 
vacuum tubes need be replaced and there is practically no cost 
of upkeep. 

The writer confidently expects that this scheme will be in use 
throughout the country very shortly. 



CHAPTER X 

HOW TO MAKE SIMPLE RECEIVING 
OUTFITS 

IN the following pages the author has endeav- 
ored to show how, with little expense, very good 
radio telephone receiving outfits may be built by any 
one endowed with a little mechanical ability. The 
author has selected the examples with an eye to- 
wards simplicity, and while these outfits are not in- 
tended to be classed with those of a high efficiency 
they are excellent for the beginner, and the man who 
likes to "make his own." 

Inasmuch as this book was written particularly 
for the beginner and the novice, it was thought that 
the more complicated vacuum tube sets and the con- 
struction thereof should best be left out until the 
reader has first gained his knowledge through the 
simple crystal outfit. 

It will be noted that all of the outfits here des- 
cribed can be made with material usually found 
about the house and in a model workshop. While a 
number of outfits are shown here, it should be under- 
stood that, with the exception of the vacuum tube 
outfits, they are all of about the same value, all work- 
ing about the same distance, and the reader is invited 
to build the outfit which he likes best, and for which 
he knows that he has most of the materials required 
on hand. 

180 



HOW TO MAKE RECEIVING OUTFITS 181 
THE "SIMPLEST" RADIOPHONE RECEIVER 

The important points of this set are: 

( 1st ) It is simple in construction and opera- 
tion. ( Mr. James Leo McLaughlin, 
a New York radio amateur has actu- 
ally built and operated this outfit). 
A knife or razor blade and a small 
nail are the only tools required to 
make it. The complete set can easily 
be constructed in about one-half hour. 
(2nd) It is inexpensive, the total cost, in- 
cluding the 'phone and antenna is less 
than $3.00, the set itself costing only 
2iy 2 cents. 

(3rd) It is as efficient as most of the crys- 
tal sets now being sold and in many 
cases superior to them. 
The material required is as follows : 

1 Paper container (4" in diameter). 
13 Paper fasteners (small size). 

2 Paper fasteners (large size). 

3 Paperclips. 

2 Oz. No. 26 enameled copper wire. 

1 Small piece of silicon or galena. 

1 Common pin. 

Take the container (the kind used to carry liq- 
uids) and punch nine holes one inch down from 
the top with a small nail, one half inch apart. Into 
each hole push a paper fastener. With pen and ink 
number each fastener from right to left, 1 to 9. 



182 RADIO FOR ALL 

Alongside of hole No. 1 push two fasteners with 
a paper clip underneath mark GND (ground). 
One half inch down from. GND, punch a small hole ; 
this is the starting point of the coil. See Fig. 111. 
Take the wire and push the end through the hole. 
Wrap the end around one of the fasteners GND 



.Pin 

Crystal 

Paperclips 




FIG. Hi. 

(on the inside of the container). Be sure that 
where the wire touches the fastener, the enamel 
lias been scraped off, otherwise a poor connection 
will result. 

Next pull the wire tight and commence winding 
the coil. The total number of turns is seventy, and a 
tap is taken off at each of the following turns : The 
15th, 20th, 25th, 30th, 35th, 40th, 45th, 55th, and 
the 70th. 

Fig. 112 shows how to tap the coil. The im- 



HOW TO MAKE RECEIVING OUTFITS 183 

portant things to look out for are that the coil is 
wound as tight as possible, and that the enamel is 
scraped off the wire, where it makes connection 
with the fasteners. The 15th turn is contact No. 1, 
the 20th No. 2, etc. 



To phones 




Receiver 



Fio. 112. 



The next job is the switch that moves over the 
contacts. Figs. Ill and 112 show how this is made. 
Take one of the large fasteners, push the ends 
through the side of the cover, close to the lid. Bend 
one end down flush with the side and push the other 
end through the top and bend over. 

Put the cover back on the container and bend 
the end of the fastener so that it rides over the con- 
tacts easily, when the cover is turned, but be sure 



184 RADIO FOR ALL 

that it touches each of them. Break off the sur- 
plus end. 

The other larger fastener is pushed through the 
lid opposite the switch and is bent, as shown in Fig. 
Ill, so that it can hold the small crystal. A short 
piece of bare wire (about No. 24 will do) , acts as the 
cat-whisker, a pin is fastened to one end and the 
other end is wrapped around the end of the switch 
the part that is bent over (see Fig. 112) . 

Fig. 112 shows the diagram of connections and 
needs little comment. 

The telephone receiver is a single Murdock or 
"Rico" without head band, and can be purchased 
for about $2.00. Of course any other kind may 
be substituted. 

For the antenna one-half pound of No. 18 bare 
copper wire will do. This will give about 100 feet 
of wire. Two porcelain cleats will also be required 
and should not cost over 5 cents. The wire can be 
had for about 30 cents. 

String the wire the greatest length possible and 
attach outer end to a tree or other elevation, at least 
30 feet high (see Fig. 112). The other end of 
the wire enters the house and is attached to the 
switch button marked ANT; a short piece of 
rubber tubing should be slipped over the wire where 
it passes through the wall of the building. 

A good ground may be had by connecting a wire 
to the nearest water pipe. Scrape the pipe for a 
length of about two inches, so that it shines, 



HOW TO MAKE RECEIVING OUTFITS 185 

then wrap several turns of wire around it 
and twist tightly. It is, however, better to use a 
ground clamp. 

To operate the set, bend the catwhisker wire so 
that the pin rests on the crystal. Move the pin over 
the surface until a signal is heard; at the same time 
move the switch over the contacts, and leave it on 
the one that brings the station the loudest. 

With this set in New York City, using only a 
single No. 24 wire, 25 feet long strung up in a room, 
WDY's and WJZ's concerts came in fine, and on 
several occasions, the phone could be held about six 
inches from the ear, and still the music and voice 
could be distinguished. 

A SIMPLE RADIOPHONE RECEIVER 
The radio receiver shown in the accompanying 
drawings (Fig. 113), was designed to tune to 600 
meters, using a single- wire serial about 130 feet long. 
This coil has an inductance of about 537,600 cms. 
and with an serial having a capacity of .0003 mfd., 
will tune to about 750 meters. A loading coil may 
be used to increase the wave length if desired. 

The only tools required to make this receiver are 
a sharp knife, a screw driver and a pair of pliers. 

A one-pound coil of No. 18 annunciator wire, 
obtainable at any electrical supply store, will be re- 
quired for the serial and ground. A pound of this 
wire will contain about 155 feet. Cut off 20 
feet for the ground connection and use the rest for 
the serial. The location of the station will deter- 



186 



RADIO FOR ALL 



Tuning coil . 
78 turns of *24 
S.C.C.wire tap- 
ped single 
turns and 
turns. Give 
coil liqhtT 
of shellac. 



tube 3i'Dia.X 
3|' high. 



About. 005' thicK 
Cut from 3"X3' 
stove m 




Condenser 



Top View 



DETAIL OF 

MICA FOR 
PHONE COND. 
I REQt) 



PHONE COND. 
T1NFOIL-2 REQ'D 



AerialA/ 




Paper 
fasteners 



Tuninq , 
^ ( 



Detector- 
Cond.^ 



Side View 
of Tuning Coil 



Ground 




Phone> 



mine how the agrial is erected. Have it as high up 
as possible, but it will give good results if it is 



HOW TO MAKE RECEIVING OUTFITS 187 

only 20 feet above the earth. For insulators use 
porcelain cleats like those used for electric light 
wiring ; if none of these are at hand, blocks of wood 
boiled in paraffin will do very well. The ground 
lead does not require insulation. Make ground 
connection to a water pipe if possible. Gas pipes 
or steam radiators may be used, but as a rule are 
not as good as water pipes. Be sure both pipe and 
wire are clean and bright when connection is made. 
For the best results all connections should 
be soldered. 

Obtain a cardboard box or mailing tube about 
3 l /4 inches in diameter and cut it so that it is 3 5/16 
inches long. Civil engineers and architects get 
their tracing cloth in thick- walled mailing tubes that 
make ideal coil winding forms. If you don't hap- 
pen to have a round cardboard box of this size about 
the house, visit your city engineer. Mark a line 
around the tube 5/16 of an inch from one end. With 
the small blade of a penknife make 19 holes on this 
line spaced 7/16 of an inch apart; these holes are for 
the contact points which are the common paper 
fasteners. Insert paper fasteners in holes but do 
not spread points. 

The coil is wound with No. 24 single cotton cov- 
ered magnet wire and ]/$ Ib. will be required. To 
wind the coil fasten one end of the wire to the first 
paper fastener. In doing this scrape the end of the 
wire, also the under part of the fastener, so that 



188 RADIO FOR ALL 

when the points are spread and the fastener pinched 
with the pliers a good contact will be made. Di- 
rectly under the first fastener and 15/16 of an inch 
from end of tube insert a pin. Bring the wire down 
from the first fastener, around the pin and make one 
turn around the tube. Insert another pin under 
the second fastener, bend the wire around the se- 
cond pin, up around the second fastener, back 
around the pin and complete another turn around 
the tube. Repeat this for the first six fasteners. 
After passing wire around the sixth fastener and 
pin, wind six turns and take off another tap; con- 
tinue in this manner to end of coil taking off tap 
every sixth turn. When completed the coil should 
have 12 six-turn taps and 6 one-turn taps, or 78 
turns in all. 

It is not necessary to scrape the wire where it 
passes around the contact points until the coil is 
wound. After completing the winding, wind a 
cord around the top of the coil to hold taps in place, 
remove fasteners one at a time and scrape wire and 
fastener, replace and pinch with pliers. Remove 
cord and give winding light coat of shellac. After 
shellac is dry remove pins and winding is complete. 
It is best to keep shellac away from the contact 
points as it is apt to cause a poor contact between 
point and wire. If the maker has a soldering outfit, 
by all means solder wire to points, but if both are 
carefully scraped a good electrical connection will 
be obtained. 



HOW TO MAKE RECEIVING OUTFITS 189 

At a stationery store purchase four window 
hooks, (paper clips). Two of these are used to 
make the detector and the other two with the long 
end cut off are used as clips to vary the inductance 
as shown in the drawing; the general arrange- 
ment of the detector is also shown. One win- 
dow hook holds the crystal. The other holds a 
short end of a pencil with a rubber eraser. The cat- 
whisker wire is stuck through the eraser and allowed 
to project about an inch. The other end of the wire 
is looped a few times around the pencil and fastened 
to the window hook. By rotating the pencil the 
catwhisker wire can be made to touch the crystal. 
If galena is used, a copper wire of about No. 30 
B & S gage should be used. Galena requires a 
very light contact. The two hooks that form the 
detector are fastened to the wood base with small 
wood screws. One end of the crystal-holding hook 
is bent in a loop to hold the telephone wire terminals. 
If ordinary insulated wire is used to connect the 
telephone the ends may be secured under screw 
heads. One of the long ends cut from the hook 
used to vary the inductance forms the other tele- 
phone terminal. Purchase galena at a radio store. 

The telephone receiver must be of at least 1,000 
ohms resistance and should be purchased from 
some reliable radio shop. 

A condenser shunted across the telephone is not 
absolutely necessary, but they are easy to make and 
improve the working of the receiver. Purchase a 



190 RADIO FOR ALL 

mica stove window size 3X3 and cut from it a circle 
2% inches in diameter. From a piece of tinfoil cut 
two circles 2 y 2 inches in diameter with a tongue % 
of an inch wide and 1 inch long. Hold the tinfoil 
pieces by the tongues and dip them in melted paraf- 
fin, be careful not to get any paraffin on the 
tongues. Lay one of the pieces of tinfoil on the mica 
circle as shown on the drawing. Warm a flat iron 
so it will just melt the paraffin and turn it face up. 
Lay the mica on flat iron with the tinfoil up and as 
the wax melts you must smooth the foil until it 
makes good contact with the mica. Fasten the other 
piece of foil on the other side of the mica in the same 
manner. Give the base a light coat of shellac and 
when it is still a bit sticky lay the condenser in place 
and smooth it down. 

Connect up the apparatus as shown in the dia- 
gram, taking particular care that all electrical con- 
nections are clean and bright. Place the crystal 
in place and rotate the pencil until the catwhisker 
touches the crystal. You will have to move the cat- 
whisker about until you find the most sensitive spot. 

The usual method of testing the adjustment of 
crystal detectors is to connect up a buzzer and push 
button with one or two cells of dry battery. One 
binding post of the buzzer is grounded. When de- 
tector is adjusted properly you will hear the sound 
of buzzer in phones. If your house is equipped 
with an electric door bell, have some member of the 
family push the button while you adjust the de- 



HOW TO MAKE RECEIVING OUTFITS 191 



TOP VIEW 




7 



Receiving tronsf. / 

Fixed condenser 



Flashlight 
battery 



Cut here 




Camera carrying case 
for MS. 2 Brownie, made 
to open on the side. 



Set open 




Closed 



Fro. 114. 



tector. Having adjusted the detector move clips 
about until you hear signals. It is well to avoid 



192 RADIO FOR AJLL 

handling crystal with the fingers, and if your crystal 
gets greasy from the fingers, it may be washed with 
carbon disulphide (carbona) or alcohol. Mr. H. 
L. Jones set up and operated this simple set with 
good results. 

A POCKET SIZE RECEIVING SET 

This is a description with drawings of a small 
pocket receiving set which the author constructed 
some time ago. He, as well as Mr. Joseph E. 
Aiken, obtained remarkable results with this set, 
considering that it is small enough to slip in a 
coat pocket. It measures about 4" X 6" X 2". 

Connected to a single- wire aerial 140 feet long 
and 40 feet high, in southern Illinois, Arlington 
(NAA) came in clearly enough to be copied 
through considerable static. Key West (NAR) 
and a large number of ships and stations on the 
Atlantic coast have also been received. It has a 
maximum wave length of 3,500 meters. 

The set is mounted in a small leather-covered 
camera carrying case, with shoulder strap (No. 2 
Folding "Brownie"), which has been arranged to 
open on the side. ( See Fig. 114) . 

The secondary coil is wound upon a wooden 
form 2% inches in diameter and is about an inch 
wide. After the secondary is removed and wound 
with tape, the primary is wound on top of the sec- 
ondary, and then the two are wrapped together. 
The primary winding has 342 turns of No. 24 
S.C.C. wire. Every other turn of the first 18 



HOW TO MAKE RECEIVING OUTFITS 193 

is brought out by leads to a nine-point switch. The 
remainder is tapped every 18 turns and each 
tap is connected to a point of an 18-point 
primary switch. This method allows fine tuning. 

The secondary coil has 400 turns of No. 28 
S.C.C. wire, divided into 10 equal sections, which 
are connected to the ten-point secondary switch. 

A fixed condenser to connect across the phones 
is made from two sheets of tinfoil, 2"X6", which are 
separated by waxed paper and folded into a 
small bundle. 

The detector is shown in the diagram and is of 
the catwhisker type, using galena. 

Binding posts for serial, ground and phones, are 
provided. A very small watch-case buzzer, and the 
smallest size two-cell flashlight battery, are included 
with which to adjust the detector. A small push 
button to control the buzzer is mounted on the panel. 

The panel on which the switches and detector 
are mounted is made of Spanish cedar taken from a 
cigar box and highly finished in mahogany. The 
panel is mounted so that the switch knobs will not 
touch the lid when it is fastened. 

ANOTHER LOW-PRICED RECEIVING SET 

The one sure way of making a convert to the 
wireless art is to have him "listen in" long enough to 
realize that the whole world is waiting to talk to him, 
and then lead him to the work bench. Doubtless 
there are thousands of lads who look wistfully at the 
supply catalogs but get no further, feeling that the 

13 



194 RADIO FOR ALL 

cost is beyond their scant means or that their elec- 
trical and mechanical knowledge is insufficient to 
cope with the construction of the various condensers, 
coils and detectors so beautifully pictured. 

The receiving set illustrated was planned for 
just these boys, the item of expense and the diffi- 
culties of construction having been eliminated. It 
was made complete in one evening with time to 
spare. It was designed to get the boys started in a 
practical way, however small, because any boy, who 
is a real boy, who receives a message on apparatus of 
his own construction will no longer be immune to 
the radio bacillus. He may throw the set away in 
a month and start after an audion, but it has served 
its purpose in making a convert. 

In almost every community, there is one or more 
good amateur station operating on 200 meters or 
less, and to receive them is such a simple matter 
that the beginner would never suspect it after seeing 
the usual array of equipment used. One need not 
be deterred by the thought of putting up an 
elaborate serial on poles a single wire run from 
the chimney to the garage, or a large loop in the 
attic will answer every purpose. 

The first thing to do is to get a piece of dry % 
inch board, 4 or 5 inches wide and 6 or 7 inches long, 
the exact dimensions being unimportant. Boil it in 
paraffin, and on the underside press on a piece of 
paraffined paper about 4 // X5 // . On this, build the 
fixed condenser, which consists in all, of three sheets 



HOW TO MAKE RECEIVING OUTFITS 195 

of tinfoil about two by three inches, with thin paraf- 
fined paper between and a heavy protective piece 
on top. Connections to the tinfoil may be readily 
made by means of a small screw and a washer at each 
end. (See Fig. 115). Fasten a small block at 
each corner, so that when the board is turned right 



To aerial 



.Spacer 
kthicK 



Variable condenser 




side up, the condenser will not rub on the bench. 
Or you can make the base in one piece as shown 
in illustration : 

The variable condenser is arranged as follows: 
First press down a piece of paraffined paper and 
then a sheet of smooth tinfoil on top of this, working 
out all the wrinkles and bringing the left-hand edge 
around over the side of the board so that connection 
may be easily made therewith. The tinfoil should 



196 RADIO FOR ALL 

contain an area of from 15 to 25 square inches, de- 
pending upon how thin the paper is between the 
plates. The upper plate consists of a smooth piece 
of heavy tin or brass, the corners and edges of which 
have been smoothed off. This is to be fastened 
down with two screws and is slightly bent down so 
that the free edge will stand about a quarter of an 
inch from the tinfoil. Cut the latter away for about 
a quarter of an inch from around the screw holes 
and coat with shellac. Cover with a piece of 1/16 
inch fibre which serves as a spacer, and press 
flat. Screw down the tin plate, and provide a screw 
adjustment so that the distance between the plate 
and the tinfoil may be altered as desired. 

The tuning coil in the usual set is here replaced 
with a small coil consisting of 50 feet or less of 
magnet wire. The capacity of the condenser being 
unknown, no definite data can be given for this; 
but it is a very simple matter to make a few tests. 
Take any odd length of magnet wire, say number 
22 or 24, and wind it on a cardboard about an inch 
and a half in diameter, and the chances are that it 
will work. If the signals keep increasing in strength 
as the condenser is screwed down, it means that 
more turns should be added to the coil. If the sig- 
nals are loudest when the condenser is wide open, 
it is probable that too many turns are being used. 
The capacity of the condenser itself may be reduced 
considerably by placing another sheet of paper be- 
tween the plate and the tinfoil. 



HOW TO MAKE RECEIVING OUTFITS 197 

We have now only to construct the detector, and 
here more than on any other feature depends the 
strength of the signals. Do not use a large crystal ; 
break it up into pieces not more than an eighth or 
a quarter of an inch and then test a dozen or more 
pieces until a sensitive face is found. To do this 
the crystal does not have to be mounted. Simply 
put it on any clean metal surface and carefully go 
over each with a whisker wire, which may be easily 
handled by sticking it in the end of a piece of wood. 
A test buzzer will be necessary, and, of course, con- 
nections must be made in the usual manner. When 
a good crystal is found, solder a brass nut or a short 
piece of tubing to a piece of sheet brass and fasten 
to the base, after which pack in the piece of galena 
with tinfoil. 

The essential requirement in a crystal detector 
for a beginner is to have it so arranged that the en- 
tire surface of the crystal may be explored quickly. 
So many detectors have the whisker wire on 
the end of a screw and are almost worthless because 
a sensitive spot is no sooner found than lost, due to 
a slight wobble of the whisker caused by turning the 
screw further to adjust the tension. If the whisker 
is about 24 f an mc h l n g the pressure is relatively 
unimportant when it has once been placed on the 
right point. In the design illustrated, a binding post 
is mounted on a block with a single head screw which 
is set in only fairly tightly in order that the shank 



198 RADIO FOR ALL 

may be moved to or from the crystal. The cat- 
whisker wire is best soldered to the shank. 

Four binding posts two for the phones, one 
for the serial and one for the ground complete 
the set. 

As previously mentioned, the cost is small, not 
exceeding 25 cents for all needed parts. The tun- 
ing is done entirely by the condenser. 

It works surprisingly well. 

A $1.00 RADIO SET 

The broadcasting of radiophone concerts has 
been given a wide publicity in the magazines, as well 
as in the daily press, and many people who never 
before had read any details about Radio and its 
possibilities, have become interested in it, and would 
like to know how these concerts may be received. 
Most of those who do not know anything about 
Radio are struck, when opening a Radio magazine, 
by the variety of equipment advertised, and espe- 
cially by the prices quoted; some of them then 
become discouraged and do not push further the 
idea of buying a receiving set. 

For these persons we shall give in this article 
a little practical data for making a home-made re- 
ceiving apparatus, which will cost about $1. Of 
course, the efficiency and sensitivity of such a set 
cannot be compared to the modern types of receiv- 
ers which are now obtainable, and in which vacuum 
tube detectors and amplifiers are used, but very 
good results may be had with such a cheap outfit, 



HOW TO MAKE RECEIVING OUTFITS 199 

provided the directions given in this article are care- 
fully followed. 

To build this small receiver, the main things 
to secure are a good telephone receiver, which may 
be bought very cheaply in a second-hand shop, and 
a mounted crystal of galena, that is, a piece of ga- 
lena inserted in a little block of lead; this may be 
bought at any Radio supply house for a few cents. 
Or else a 50 cent "Rasco" Detector will do. 

The home-made detector may be built very sim- 
ply, as shown in the sketch, Fig. 116 A. Two nails 
should be driven into a piece of wood used as a base 
and the mounted crystal tightly secured to one of 
the nails by a tight winding of copper wire fixed 
around both. The exploring wire, better known 
among amateurs as the "catwhisker" consists of a 
piece of the same wire wound around the other nail, 
as shown, and bent so that its tip lies down on the 
crystal with a certain pressure ; this end of the wire 
should be sharpened with a nail file, so that the tip 
is about as sharp as a pin. About 2 inches of the 
wire from both nails should be left out to make con- 
nections with the outside circuit. 

THE ANTENNA 

The antenna to be used with such a receiving set 
may be of several types, according to the space 
available for the erection of the wires, which com- 
pose it. If in the open, the simplest type of antenna 
to erect is a single wire about 150 feet long, 
attached as high as possible between trees, houses or 



200 



RADIO FOR ALL 



,Nail 



Nail 



Piece of wood- 



Copper wire 



String 



No. 20 wire 




Telephone 
receiver 



Telephone cord 




E 

Insulation 
scraped 
off wire 




Wooden base-^ 

2 Turns between each noil 



DETAIL OF TAPS 




Beginning of 

winding 

/ 6 turns- 
/ 4 turns *T 4 
2 turns ' 

' tl 

ZOOturnsf 20 
180 turns 
160 

140 turns 

120 turns 

DETAILS OF WINDING 

OF THE TUNING COIL. 



turns 
10 turns 
12 Turns 
I4 turns 
l6 Turns 
18 turns 

20 turns 
40 turns 
60 turns 
80 turns 
100 turns 



To aerial F 
V Detector^ 



D 




Receiver 



other natural supports which may be at hand; at 
each end of the wire, an insulator should be fixed, 



HOW TO MAKE RECEIVING OUTFITS 201 

and may consist of a piece of dry wood about 10 
inches long, preferably, or two porcelain cleats. 
These insulators are then inserted between the 
string fixed to a nail and the wire itself, as shown 
in Fig. 116 B. 

Almost any kind of wire may be used for an an- 
tenna and either insulated, bare, or enameled wires 
are quite suitable, provided they are strong enough 
not to break when stretched; No. 18 or 20 B.S. is 
quite suitable. If the set is to be installed indoors, 
the wire should be well insulated where it enters the 
house and it would be advisable to use a piece of 
rubber covered cable as employed in motor cars to 
connect the spark plugs. 

If in a town or other place where it is not possi- 
ble to stretch a long wire between trees or poles, a 
greater number of shorter wires may be used, but it 
should be remembered that the higher these wires 
are erected, the better. If only a small surface, 
such as a roof, is available for the installation of the 
antenna, four or five wires parallel to each other and 
about two to four feet apart will make a good 
antenna. They should all be connected together at 
one end and the connections soldered, if possible; 
from this end the "lead-in," that is the wire carrying 
the current to the instruments, comes down into the 
house. See Fig. 116 B. 

Another case is that if it is impossible for one 
reason or another to install an outside antenna, an 
indoor one may be rigged up and may be of the same 



202 RADIO FOR ALL 

type as the last one described. Of course, the effi- 
ciency of such an antenna is very poor with a crystal 
receiver, but some results may be obtained if the 
receiver is not more than three or four miles from 
some transmitting stations. With an indoor serial 
composed of four wires 35 feet long and using the 
inductance described in this article, the author 
received the Radiophone transmission from WJZ 
eight miles away. 

THE GROUND 

The ideal ground connection is a large surface 
of zinc or copper plates buried in damp ground, 
about two to three feet deep. Another good ground 
may be made with long wires buried in the same way. 
These grounds are only possible for the fellow in the 
country, but for the city dweller, the only possible 
grounds are the water pipe or the radiator system. 
In any case, the preference should be given to the 
water pipe, but if it is impossible to reach it with 
a rather short connection, the radiator should be 
used. The pipe should be scraped to insure a good 
contact and the connections soldered if possible. 
The best is a ground clamp. 

How IT WORKS 

Once your detector is made and your antenna 
erected, with your ground wire fixed to a pipe, all 
that it is necessary to do, is to listen in the receiver 
while adjusting the detector. This adjustment 
merely consists in moving the sharp point touching 



HOW TO MAKE RECEIVING OUTFITS 203 

the crystal until some signals are heard. If in a 
city, or in the neighborhood of transmitting sta- 
tions, some signals almost certainly will be heard 
with the first attempt, provided the crystal of galena 
is a sensitive one. 

With such an outfit, there are no tuning possi- 
bilities since no means of tuning are available and a 
great improvement to the set would consist in a 
tuning inductance, which may be made as explained 
hereafter. This inductance is not indispensable 
and spark signals as well as radio telephony were 
heard by Mr. Robert E. Lacault with the detector 
alone, but in many cases the intensity of the sig- 
nal will be increased many fold by the use of such 
a "tuning coil/' 

CONSTRUCTION OF A SIMPLE TUNER 

Fig. 116 C shows a type of home-made induc- 
tance, which can be contructed very cheaply. It 
consists of a piece of wood forming the base, and 20 
brass nails about 1 y 2 or 2 inches long, driven into the 
board in a circle, as shown in Fig. 116 D. To wind 
the inductance, about 265 feet of No. 24 or No. 26 
double cotton covered wire, is necessary. The be- 
ginning of the winding should start at one of the 
nails, as shown in Fig. 116 C-D, the wire, which 
should be scraped of its insulation, should be twisted 
around the nail to make contact, and fastened. 
Thejn, two turns around the circle formed by the 
nails should be wound and the wire fixed to the next 



204 RADIO FOR ALL 

nail, No. 2, as shown in Fig. 116 E. Twenty turns 
should be wound in the same manner with contacts 
every two turns made to the first row of 10 nails, 
numbered 1 to 10. From the nail No. 11, 20 turns 
should be wound before a contact is made on the 
Nail No. 12 and thereafter the same number of 
turns should be wound between each step. 

This will form a total inductance of 200 turns 
and almost any number of turns may be inserted in 
the circuit by connecting the necessary sections of 
20 and 2 turns between the antenna and ground 
clips. These clips making contact on the nails and 
shown in Fig. 116 E, are ordinary paper clips and 
make very good contacts on the nails. The diagram 
of connections of the complete set, including the 
tuning inductance, is shown in Fig. 116 F. 

To tune the set when signals are heard in the 
telephone, the clip making contact with the nails 
connected every 20 turns of the coil, should be va- 
ried, so as to increase the intensity of the signals; 
then, a fine adjustment is obtained by changing the 
position of the other clip which varies the number 
of turns in the circuit only two at a time. 

This little set, which is easy to build, will provide 
a lot of entertainment to those interested in Radio 
and if near enough to a Radiophone broadcasting 
station, the voice will be heard quite clearly. 

AN EFFICIENT JUNIOR RECEIVER 

Today in almost any magazine you chance to 
pick up it is possible to find the advertisements of 



HOW TO MAKE RECEIVING OUTFITS 205 

junior receivers of some kind. Most of these are 
nothing more than a tuning coil and detector 
mounted in some kind of box or cabinet. These are 
easily made and are quite efficient on short waves for 
some distances. This is the reason the author is des- 
cribing the junior receiving set he constructed of 
material taken from old apparatus. Yours may be 
of old material or of material bought for the purpose. 

To begin with, a cabinet is constructed to the 
inside dimensions of 6 by 9 inches, by 6 inches in 
depth, Fig. 117. The material the author used 
was birch one-quarter inch thick. It is put to- 
gether with small screws and glue. When the glue 
has set it is stained a mahogany color and varnished. 
This coat is allowed to set for three days and is then 
rubbed down with pumice and water, then varnished 
again. If this is done carefully, you will have a 
cabinet closely resembling a factory product. 

The front panel is of bakelite or formica one- 
quarter inch thick and cut six inches wide and nine 
inches long. Before drilling, a template of the front 
panel is made of heavy paper and the location of the 
instruments are figured out and marked on this, so 
as to reduce the chances of mistakes. The template 
is then laid over the panel and the transferring is 
done with some sharp pointed tool. The drilling of 
the holes for the panel mounting screws, the switches 
and switch points, variable condenser and detector 
is accomplished with some small sharp drill. The 
panel is best attached to the box as shown in Fig. 
117 C. 



206 



RADIO FOR ALL 



Method of fasten- 
ing panel incabine" 



Method of 
fastening 
coll to bocK 
of panel. 




The tuning coil is of No. 24 
magnet wire, wound on a 



enamel insulated 
cardboard tube 



HOW TO MAKE RECEIVING OUTFITS 207 

six inches long and three and one-half inches in dia- 
meter, the winding is tapped at 20 equal spaces. 
The switch levers, switch stops and switch points 
are put on the front panel and the taps are con- 
nected to the switch points and the coil is mounted 
behind the panel with wooden blocks as shown in 
Fig. 117 B. This completes the tuning coil and 
controlling switches. 

The variable condenser is, or can be, any stan- 
dard condenser having a capacity of about .0005 
mf . ; the author's was a Murdock panel type having 
that capacity. The condenser is mounted back of 
the panel and the indicating dial is screwed on to 
the shaft. 

The detector can be of any good reliable type of 
crystal (preferably galena) detector. It may be 
either an old one or it may be purchased for this pur- 
pose. It is taken from its base and mounted at the 
top of the front panel. 

A small fixed condenser having a capacity of 
about .0015 mf. is used for the phone or stopping 
condenser. This is screwed to the bottom of the 
cabinet and is used to shunt across the phones. This, 
completed, makes the set ready for work on wiring 
after the binding posts are put in place as shown on 
the drawing of the front panel. 

Run a wire from the switch lever on your left 
to the binding post at the upper right and mark this 
A. The other switch is connected to the other bind- 
ing post and marked G. A wire is run from the 



208 RADIO FOR ALL 

left side of the tuning coil winding to one of the 
variable condenser terminals, then to one binding 
post on the detector. From the other detector bind- 
ing post a wire is run to the phone condenser and 
then to the phone binding post on the left. An- 
other wire is run from the other variable condenser 
binding post to the right hand end of the tuning 
coil winding, to the phone condenser and then the 
other phone binding post. The set is now com- 
pletely wired and the cabinet may be closed and 
sealed as shown in Fig. 117 A. 

For use the aerial is connected to the binding post 
marked A and the ground to G. The phones are 
connected to the binding posts on the bottom of the 
panel. Most of the tuning is accomplished through 
the switches, while the variable condenser is used 
mainly to tune out interference. All connections 
are shown in Fig. 117 D. 

A PORTABLE RECEIVING SET 

Herewith is described a receiving set, the con- 
struction of which is somewhat radical, as it uses 
no aerial of any kind. It is only in an experimental 
stage, but Mr. Eugene M. Kiel has found it very 
useful for short distances. A radio club or a troop 
of Boy Scouts on a hike always want to keep in 
touch with the nearby home station, and with this 
set all that is necessary is to raise the lid and connect 
the batteries; there being no serial to unfold and 
hoist in the air. 

The box is 10"X10"X18" over all, constructed 



HOW TO MAKE RECEIVING OUTFITS 209 

of l /2 inch hardwood with one side on hinges so that 
it can be raised when in use, the case lying on the 
other side. Brass corner-pieces and angle strips 
make the case stronger and add much to its appear- 
ance. It is also fitted with a handle for carrying and 
a hinge hasp. 

Two and a half inches from the top a l /$ inch 
Bakelite panel is mounted by means of l / 2 inch 
cleats. On this panel are mounted the following 
instruments, as shown in Fig. 118: (1) The loop 
coil which is used for an serial; (2) a variable con- 
denser of .001 mf. capacity for tuning; (4) a rheo- 
stat for the filament of the audion bulb. The bulb 
itself (3), or, rather, the socket for the bulb, is 
mounted in a recess 4 inches below the top of the 
panel, as shown. Binding posts are provided for 
attachment of "A" and "B" batteries and also the 
telephones, for which a space is provided by the 
setting of the panel below the top of the case. 

The coil (1) is preferably a Litz wire- wound 
coil of small distributed capacity, but not of the 
honeycomb or lattice type, because the zigzag wind- 
ing of the wire will not permit a directional effect. 
Sixty-five turns of wire, bank-wound on a circular 
wooden form 2 inches in diameter as shown, will be 
about right for 200 to 400 meters wave-length. 

The connections are self-explanatory, the con- 
denser ( 5 ) being the grid condenser. 

If desired, there is room in the case for the "B"- 
battery. Any amount of wire can be wound on 
the coil, to receive any wave-length desired. 

14 



210 



RADIO FOR ALL 



Variable _ 
condenser 




Variable 
condenser-2 

Phones 



Front View Sectional Side View 
RECEIVING COIL 

Rheostat 



aft 

i WAAA/ -^5" 



PIG. 118. 



To receive, adjust the plane of the coil in the 
direction of the sending station and tune the signals 



HOW TO MAKE RECEIVING OUTFITS 211 

in with the variable condenser. It must be under- 
stood, of course, that this set will not respond to 
signals transmitted from great distances. Good 
receiving depends primarily on the power of the 
local transmitter as well as upon the most effective 
tuning of the receiver and functioning of the 
vacuum tube. 

A SIMPLE AND EFFICIENT SHORT WAVE 
REGENERATIVE RECEIVER 

Here is a short wave regenerative receiver 
which can be constructed by the amateur very 
economically. When the outfit described below is 
carefully made up, it is a credit to an operating 
table and is one that the most exacting of radio fans 
will take great delight in showing his friends and 
fellow bugs. It is easily made up, requires but very 
few parts, and is so assembled that it is easily acces- 
sible at all times for the changing of hook-ups. The 
builder has his choice of mounting the outfit, which 
is designed along the lines of the famous Paragon 
short wave regenerative receiver, in cabinet form or 
assembling it upon a pair of braces or brackets. It 
has not been put to any extensive test, but Mr. 
Frederick J. Rumford has worked on 100 to 400 
meters with very good results, and the author feels 
sure that the builder can get still better results by 
further experimentation. 



212 RADIO FOR ALL 

ARTICLES NEEDED 

In making the outfit, one needs two 3-inch Bake- 
lite dials engraved as shown and one 2 -inch dial also 
engraved. These dials must have knobs attached 
to them. Eight brass or copper binding posts, such 
as are used with any radio receiving apparatus, are 
also required and one complete variable switch as- 
sembly with five contacts and their necessary nuts 
and washers. These would look best if they were 
nickel plated. The switch lever will swing within 
a radius of one inch. This switch is for the purpose 
of tapping the primary of the loose ( vario- ) coupler. 
One of the contacts on the switch is left idle. Now 
we will start on the panel and continue until the 
whole outfit is ready for instant use. 

THE PANEL 

Fig. 119 A shows the exterior view, or front of 
the panel with the necessary articles mounted in their 
respective places and the symbols indicating them. 

Fig. 119 B represents the interior view, showing 
the variometers and loose coupler mounted in their 
places, and the method of mounting them. 

Fig. 119 C shows both the internal and external 
hooking-up for the outfit. The builder following 
this hook-up should get very good results. 

The panel may be bakelite, rubber, oak or box- 
wood and should be 12 inches long, 6 inches wide 



HOW TO MAKE RECEIVING OUTFITS 213 




Vorio- 
coupler 



'B' Bottery- 



FIG. 119. 



and from ^ to ^ inches thick. The measuring 
and drilling for the necessary holes should be done 



214 RADIO FOR ALL 

first, then the panel sandpapered and given two or 
three coats of varnish or paint. The panel described 
was made of oak and had three coats of black, glossy 
varnish. For the shafts on the variometers there 
should be ^4-inch holes drilled, for the binding posts, 
3/16-inch holes and for the switch contacts and 
switch lever %-inch holes. After the drilling and 
painting are done the panel is ready to be engraved. 
The symbols should be neatly engraved on the front 
of the panel with a sharp-pointed slender tool and 
filled in with white india ink or a similar substance. 
The panel is then ready for the mounting of the 
binding posts and switch assembly. 

MAKING THE COILS 

We will pass to the making of the different coils 
necessary for the successful operation of this outfit. 
The amateur must procure six cardboard tubes in 
the following sizes: two, 4 inches in outside dia- 
meter and 2 inches long with a wall y% of an inch 
thick ; one form, 3 inches in outside diameter and 2 
inches long with a wall ^ of an inch thick; two, 
2^4 inches in outside diameter and 2 inches long with 
a wall y% of an inch thick ; one, 4 inches in outside 
diameter and 3^ inches long with a wall y% of an 
inch thick. All forms that are 5 inches in outside dia- 
meter are the different primaries for the different 
variometer assemblies, and the forms smaller in out- 
side diameter are the secondaries. Now take the two 
primaries that are 2 inches long and drill a hole in the 



HOW TO MAKE RECEIVING OUTFITS 215 

center of them to allow a loose fit of a }4' mc h shaft. 
This shaft is the means by which the secondary is 
revolved within the primary and the hole to be drill- 
ed in the secondary forms should be small enough to 
allow for a snug fit on the same size shaft. After 
this has been done, the four coil forms should be 
given a couple of coats of some good insulating com- 
pound. After they have dried they are ready for 
the wire to be wound upon them. 

In this instance, the author used No. 24 
D.C.C. magnet wire, On the primary form of the 
variometer number one, the winding should start in 
Y% of an inch and continue over for ^ of an inch ; 
then skip a space of ]/ 2 inch and continue winding 
until y% of an inch from the end. The author 
thinks it advisable to have a little brass (never iron) 
machine screw on both ends of each of the coils with 
suitable nuts and washers to which to attach the 
wire upon the starting and finishing of the winding. 
It also provides means of hooking the primary and 
secondary in series. This will make about 42 turns 
in all on the primaries of variometers No. 1 and No. 
2, making 2 1 turns to a section. Both primaries are 
wound alike. As the reader will note in Fig. 119 
B, the coils are all wound in two sections; the space 
in the center is left to allow room for fastening the 
shaft securely. After being wound, the primaries 
should be given a coat of shellac but care taken 
not to get too much on them as it would cause 
energy losses. 



216 RADIO FOR ALL 

THE SECONDARIES 

Now comes the making of the secondaries for 
variometers No. 1 and No. 2. These coil forms are 
2^4 inches in outside diameter and 2 inches long. 
The winding on the coils starts y% of an inch in and 
continues over for % of an inch, leaving a %- 
inch space. It again continues over ^J of an inch, 
leaving yfc of an inch at the end. These coils are 
fastened at both ends by the same means as 
used on the primaries. The secondaries should also 
be shellacked. 

THE LOOSE COUPLEE 

The next step is making the loose coupler. The 
primary is 4 inches in outside diameter and 3j/2 
inches long with a wall l /% of an inch thick. The 
primary should have a lip on it as, shown in Fig. 
119 B, the purpose being a means of fastening the 
shaft. This coil form should be treated like the 
others. After it has dried, the winding will start on 
the lip end by attaching the wire upon the machine 
screw or post as was mentioned above,, as was 
done on the other coils. It should be wound 2 
inches down with No. 24 D.C.C. magnet wire. In 
fact, all the coils are wound with this size wire and 
must also be wound in the same direction. After 
this coil has been wound, it is ready for the shellack- 
ing. On this coil four taps will be taken off. As 
the two inches of winding will equal 66 turns of 
wire, the taps will be taken off on the 16th, 33rd, 



HOW TO MAKE RECEIVING OUTFITS 217 

49th and 66th turns. A good way to take them off is 
to scrape the insulation back on the wire on the above 
numbered taps or turns and solder short pieces of 
No. 14 bare copper wire upon the scraped section, 
which will in turn connect to the different contacts 
on the panel. 

We are now ready to make the secondary coil 
for the loose coupler. This coil form is 3 inches in 
diameter and 2 inches long with a wall y% of an inch 
thick. It should have a hole drilled in the center 
of it to allow for the passing through of a J4 of an 
inch, snug-fitting shaft. This shaft is for the pur- 
pose of revolving the secondary coil within the pri- 
mary coil and should be drilled for accordingly on 
the primary. The winding, to be fastened the same 
as in the case of the other coils, will continue over 
for % of an mcn skip a space of 1 A of an inch and 
continue for ^ of an inch more. This end will be 
fastened upon the post fitted for it. The second- 
ary is now ready for its coat of shellac. 

As was said above, all the coils are wound with 
No. 24 D.C.C. magnet wire. The primaries on va- 
riometers No. 1 and No. 2 will have 42 turns upon 
each of them, which will be 21 turns per section, 
making a total of about 45 feet of wire to each pri- 
mary, or 90 feet for the two. The two secondaries of 
variometers one and two will have 50 turns each, 
with 25 turns to a section. Each coil will take about 
36 feet of wire or 72 feet for both. The loose coupler 
primary has 66 turns of wire, which would equal 



218 RADIO FOR ALL 

about 71 feet. The loose coupler secondary has 50 
turns of wire, 25 turns to a section which would 
equal about 40 feet. In all, it requires 273 feet or 
close to one-half pound of the wire. 

ASSEMBLING THE PARTS 

The outfit is now ready to be assembled. The 
binding posts and switch assembly have already 
been mounted. Now mount the primaries or vario- 
meters No. 1 and No. 2, by four little wood screws, 
two to a coil, which will screw in through the coil 
form into the back of the panel, so as the shaft hole 
on the coil form will come in line with the hole in the 
panel. After that, get the necessary shafts, which 
should be threaded their whole length. Each one 
of these shafts should be 5 inches long and ^4 of an 
inch in diameter. One end of the shafts should be 
screwed into the knob on the dial and soldered so 
that it will not work loose. It is then in turn pushed 
through the panel from the front through the pri- 
mary coil and nuts run on it so there will be a nut 
on the front and back of the secondary at each end, 
and on the inside and outside of the primary, which, 
when drawn up tight to the forms, will hold them 
securely. The above operation should be executed 
on both variometer assemblies. In hooking the pri- 
maries and secondaries in series, take pieces of No. 
18 flexible lamp cord of sufficient length and con- 
nect the ends of it upon the screws or posts that are 
provided in the coils. 

In assembling the loose coupler: There is a 



HOW TO MAKE RECEIVING OUTFITS 219 

rest made of 8 inches long, 4 inches wide and ^ of 
an inch thick, which in turn is secured to the back 
of the panel by two wood screws, which go through 
the panel from the front. This rest in turn will 
support the primary of the loose coupler. The pri- 
mary is then mounted upon the rest and held there 
by four little braces, two of them angle form and 
the other two straight. These braces may be cop- 
per, brass or iron. The builder must bear in mind, 
that between the back of the panel and the front of 
the primary coil form, there must be just three 
inches of space. This is absolutely essential or 
otherwise, when the secondary on variometer No. 1, 
is rotated it will in turn rub against or strike the 
primary on the loose coupler. After this has been 
done, the secondary of the loose coupler is mounted, 
the same as the secondaries on the two variometers. 
The wiring for the back of the panel is done with No. 
14 stiff bare copper wire, which can be bent into the 
different shapes desired by the builder. Figure 119 
B, shows the true method of mounting the primary 
of the loose coupler. The taps on the primary are 
hooked to their respective contacts on the panel. 
Fig. 119 C, shows the method of hooking-up the 
outfit. Any trouble the author has encountered in 
the working of this receiver he has found to be due 
to run down "B" batteries. There should be little 
or no trouble for the amateur in building this re- 
ceiver as the drawings are self-explanatory. 



220 RADIO FOR ALL 

PRACTICAL V. T. DETECTOR AND 
TWO-STAGE AMPLIFIER 

The accompanying drawing, Fig. 120, shows 
to good advantage a detector and two-stage ampli- 
fier, which have been in use for over a year; from 
this set, Mr. Frederick T. Rumford, the builder, has 
obtained the very best results. He designed it for 
the purpose of combining efficiency, simplicity and 
compactness. It requires but very little work to 
build, and its actual cost is less than $50. This price 
includes the tubes, and as every amateur knows, in 
the average detector two-stage amplifier sets, the 
tubes are an extra expense. 

Below is the list of necessary items, with their 
respective costs. 

2 " Rasco " Amplifying Transformers @ $2.65 $5.30 

1 V. T. Detector tube @ 7.00 7.00 

2 V. T. Amplifier tubes @ 7.00 14.00 

3 Murdock V. T. sockets @ 1.00 3.00 

3 Telephone jacks @ .85 2.55 

2 Formica panels, 7" x 4y 3 " x %" . . . ' @ 1.50 3.00 

3 Grid leaks and condensers 0.0005 mfg., 1 

megohm @ .50 1.50 

1 Telephone plug @ .75 .75 

25" of round %" brass stock or rod .30 

15" of flat brass stock %" wide i/ 8 " thick -25 

5" bare copper wire B. & S. No. 8 .30 

Screws and bolts .50 

8 Large size binding posts @ .20 1.60 

2 Rheostats for back mounting @ 2.00 4.00 

Actual cost $44.05 

This outfit is so compact that the builder has 
often carried it from city to city in his travels. 



HOW TO MAKE RECEIVING OUTFITS 221 




Those who build this set can mount it in a cabinet, 
if they so desire. It may be easily duplicated and 



222 RADIO FOR ALL 

requires but a few tools in the making, such as a 
screw driver, etc. It is composed of all standard 
parts, which can be readily purchased in any radio 
supply store, but, no doubt, most amateurs have the 
necessary parts lying around. It will take only 
very little time to assemble this outfit when ready. 

With the accompanying data are four drawings 
as follows: 

Fig. 120 D shows the front panel with the differ- 
ent apparatus mounted, with the correct dimensions. 

Fig. 120 C side view and also the interior, show- 
ing the positions of the tube, transformers, rheo- 
stats and jacks. 

Fig. 120 A represents the interior looking down 
from the top. 

Fig. 120 B represents the rear panel, showing 
the different dimensions for the placing of the 
binding posts and positions of the different 
attaching screws. 

Fig. 120 E shows the general hook-up with pro- 
per connections. 

We will now pass on to the actual making of 
this set. The two 7"X4^"X}4" panels are given 
a dull grain finish with No. sandpaper, and then 
rubbed with oil. After this, the usual mark- 
ing off and drilling of holes is done as shown in 
Figs. 120 B and 120 D. The rheostats and jacks 
are mounted on the front panel as shown and the 
binding posts are next mounted on the rear panel, 
which panel will be cut out at the corners, see Fig. 



HOW TO MAKE RECEIVING OUTFITS 223 

120 B. This gives the panel a distinctive appear- 
ance and also provides for air in case the outfit is 
mounted within a cabinet. 

The round J^-inch brass rod is now cut into 
four 6-inch lengths, being drilled and tapped at each 
end to take ^-inch machine screws. If the out- 
fit is not mounted in a cabinet, it would be advis- 
able to have these rods nickel plated. For that 
matter, it would be a good idea to have all the metal 
parts that are exposed to view nickel plated, as this 
will set the outfit off to its best advantage. 

The eight binding posts, of which four are on 
each side of the rear panel, are indicated by the 
engraving upon this panel as follows : On the right 
side: A is for the "A" battery, which in this parti- 
cular instance is a 6-volt 60-ampere hour Eveready 
storage battery; B, for the "B" battery, which hap- 
pens to consist of 20 No. 703 Eveready flashlight 
batteries, wired in series multiple. The reason for 
this is that with three tubes functioning, the "B" 
battery will not stand up very long, and it also weak- 
ens the amplifying power of the outfit. There is a 
jumper wire which runs from the "B" battery nega- 
tive to the "A" battery negative. 

Now the posts on the left-hand side are as fol- 
lows: No. 1 is for the tickler connection, P, plate, 
G, grid, and F, filament. As will be seen, there are 
but very few binding posts, not at all like the old 
amplifier sets, which had a large number of posts, 
and were complicated and awkward to operate. 



224 RADIO FOR ALL 

All the tubes are of the same filament voltage and 
the plates are of the same "B" battery voltage. 

We will pass to the making of the strips for the 
socket shelf. This is cut, drilled and tapped as per 
Figs. 120 A and 120 C. The sockets are then plac- 
ed upon the strips and held in place by means of 
screws and nuts; the size is left to the individual's 
own judgment. 

The sockets are to be spaced equally apart, leav- 
ing a little margin of space at each end. The as- 
sembly in turn is mounted between the two panels 
as in Figs. 120 A and 120 C, and held there by 
means of screws, which are passed through the panel 
and secured on the back by nuts. The brass rods 
may now be screwed between the panels. The two 
" Rasco " amplifying transformers can then be 
fastened to the back of the rear panel by means 
of screws and nuts, which are properly spaced, as 
shown in Fig. 120 B. As mentioned, the holes 
above the jacks will give the necessary ventilation 
and also serve as windows so the brightness of the 
tube filaments may be observed. 

Now that the outfit is assembled, the next step 
is the wiring, which is done with No. 8 B. & S. bare 
copper wire, which it is advisable to run as straight 
and direct as possible as this wire is very stiff. It 
would be advisable to straighten the wire out, mak- 
ing it firm and rigid. 

The ingenious arrangement of the different 
parts makes most of the leads comparatively short 



HOW TO MAKE RECEIVING OUTFITS 225 

and direct. The wiring is extremely simple. The 
positive terminals of the filaments are connected to- 
gether on the sockets by one wire running straight 
across ; one wire runs from the negative terminal to 
the front panel and across the width, having the two 
rheostats connected from it onto one side of each. 
The other side goes to each individual tube socket, 
having one side of the amplifying transformer se- 
condary connected to it. The three jacks are con- 
nected on one side to the plates of each individual 
tube, and on the other side, to one wire which runs 
direct to the positive binding post of the "B" bat- 
tery ; the two center strips of the jacks are connected 
to the two individual amplifying transformer pri- 
maries. The other side of the amplifying transform- 
er secondaries are connected on one side of the grid 
leak and grid condenser which connect directly to 
the tube grids of each individual tube. The end 
jack connects on one side direct to the plate of the 
last amplifying tube, and the other side connects 
direct to the positive side of the "B" battery. 

We have omitted showing the position of the 
grid leaks and grid condensers, which are combined, 
but in the outfit described, the builder has secured 
them to the inside of the rear panel. The maker 
may use his own judgement regarding this. 

The grid leaks of this outfit are 1 megohm resis- 
tance and the grid condensers are of 0.0005 mfd. 
capacity. They were purchased from the Radio 
Specialty Co.; the jacks and plug were purchased 

15 



226 RADIO FOR ALL 

from the Federal Telephone & Telegraph Co., and 
the sockets from the Murdock Co. The rest of the 
necessary supplies were obtained from the nearest 
radio supply house. In this particular instance we 
used the Magnavox Radio Telemegaphone with one 
set of binding posts connected to the extra telephone 
plug, and the other set connected to a 6-volt 40 am- 
pere hour storage battery, which had a rheostat con- 
nected in series, making various adjustments and 
continuous service possible. When the amateur 
wishes to use this loud speaker, he plugs into either 
jack he desires and, presto, the signals will be heard 
all over the room. With this arrangement, the nec- 
essity of having the receivers clamped on the head 
all the time will be eliminated and will make it also 
possible to entertain any number of friends, when 
radio music is being transmitted. No doubt, you 
have noticed by this time that very little adjustment 
is required in operating this outfit. After you have 
adjusted the detector and the amplifier rheostats, it 
is then ready for use at any time. The builder has 
used " Rico " phones for the headset. 

By shunting a variable condenser across the 
posts marked No. 1 and F, you will obtain a regen- 
erative effect, or shunting at the tickler coil which 
may be a honeycomb coil across No. 1 and P and a 
honeycomb coil across G and F will act as a second- 
ary having the usual primary will make it possible 
to tune any wave-length 100 to 20,000 meters with 
the usual variable condenser to make sharp timing 



HOW TO MAKE RECEIVING OUTFITS 227 

possible. It will be noted that all the apparatus is 
fastened to either the front or the rear panels and 
almost all the connections are made direct from the 
binding posts on the rear panel, making it possible 
to remove the different apparatus from time to 
time, whenever it is necessary to inspect them, or for 
the replacing of a new V. T. or for renewing 
old parts. 

If traveling any distance, the outfit can be eas- 
ily knocked down and the different parts stowed 
away in the corners of a bag or trunk. The com- 
plete diagram of the proper connections is shown in 
Fig. 120 E, with the proper symbols; the let- 
ters and numbers are the same as on the panels them- 
selves. To get the proper wiring for the backs of 
the panels it would be advisable to reflect the draw- 
ing in a mirror, or to place it on top of a plain piece 
of paper, right side up and under this paper, have 
a sheet of carbon paper, carbon side up. This last 
will give the best results as the tracing of the ori- 
ginal drawing will make the proper impression upon 
the under side of the plain sheet of paper. This 
idea would apply to any or all diagrams. 

The author has covered all the necessary details 
pertaining to this particular outfit, but will say a 
few words more to the effect that its advantages 
are neatness, fine finish, compactness, workman- 
like construction, moderate price and efficiency. To 
really understand and appreciate its worth, it 
would be advisable to compare it with some of those 



228 RADIO FOR ALL 

sold in stores. The beginner can make this outfit 
without the least danger of making a "bull" of it, 
as all the parts are of well-known makes and widely 
advertised in all the radio publications and it only 
requires patience and time to assemble. 

The author feels sure that all these outfits can 
be built without the least difficulty, as all the draw- 
ings are self-explanatory. 



CHAPTER XI 
THE FUTURE OF RADIO 

As the author has mentioned often in his various 
editorials published in Modern Electrics, the Elec- 
trical Experimenter, Science & Invention, as well 
as Radio News, the radio business may be likened 
to the amateur photographic business. Within 
the next few years, we shall see every drug 
store selling complete radio outfits that can 
be put on top of the phonograph at home, 
and which can be worked by your six year 
old sister. All that is required of you is to mani- 
pulate a few knobs, and from a concealed horn, the 
latest j azz band music will then issue forth. To be 
sure, this music is broadcasted from a central sta- 
tion which may be a thousand miles away 
or farther. 

Then too, the day of the radio newspaper is 
quickly coming. Important news of the day will 
be broadcasted by radio telephone daily at stated 
intervals, as will be weather reports and other infor- 
mation useful in every community. But of course, 
the development of radio will not stop at radio tele- 
phony alone. Great and wonderful things are com- 
ing in radio which are undreamt of today. New 
uses are constantly being found. New improve- 
ments are being made almost over night. We cease 
to wonder when we hear of some new marvel that is 



230 RADIO FOR ALL 

being performed by radio, and simply shrug our 
shoulders and say "well that was predicted long 
ago." Thus, recently, a physician several hundred 
miles inland listened to the heart beats of 
a man lying unconscious on a ship three miles out 
on the ocean. Every heart beat was transmitted 
clearly and faithfully by radio to the physician, who 
was thus enabled to make a diagnosis. 

We now move ships and steer airplanes by radio. 
Very recently in Germany, radio was used in 
mines underground to locate ores and coal veins ac- 
curately, surely a surprising use for the art! In 
this invention use is made of a receiving and sending 
station, both located underground, one signalling 
to the other. When the signals pass through a coal 
field, a variation is heard at the receiving end and 
by triangulation, the exact location of the coal veins 
can be found. 

Recently, in Italy, radio has been used for pros- 
pecting metal ores. Here the Italian inventors 
use very sensitive vacuum tube outfits, and by 
means of a certain condenser arrangement, it be- 
comes possible to plot accurately the exact location 
of the future mine. Today, every radio station has 
its ubiquitous a?rial on top of the house. This soon 
will be a thing of the past. Already two American 
inventors have demonstrated that far better results 
may be had by putting the aerial underground. In 
their experiments, the inventors use the so-called 
underground loops. Of course, these are necessary 



THE FUTURE OF RADIO 231 

for long distance reception, but for your radio out- 
fit on top of the victrola in the parlor, no under- 
ground loop, or serial on the roof is necessary. The 
serial will be right inside of the outfit. We are al- 
ready doing this very thing today, and the outfit 
need not be larger than a foot square. That gives 
us sufficient space for the concealed serial within the 
box. This is not a dream of the future, as it has 
already been accomplished for the reception of radio 
music over distances of several hundred miles. 

It is even possible to do away with the loop en- 
tirely. There has appeared lately upon the market, 
an electrical plug which is simply screwed into any 
lighting fixture in your house. It makes no differ- 
ence if your lighting current is 110-volt alternating 
current, or 110-volt direct current, or even 220-volts. 
This plug consists simply of a condenser arrange- 
ment, and the idea of it is as follows : We have seen 
in former chapters that any serial wire will pick up 
radio waves. Now then, every lighting circuit 
forms a sort of loop serial itself. This is particularly 
true in the country where the wires run for great 
distances out doors. By proper arrangement, as 
for instance, using such a plug, the radio waves are 
conveyed right over the lighting circuit without in- 
terfering with the electric light bulbs, and other elec- 
tric appliances in your house. These condenser 
plugs are already a great success but they do not 
work under all circumstances. For instance, in 
apartment houses in which much steel enters into 



232 RADIO FOR ALL 

their construction, the results are not so good as in 
the country where we have a stone or wood 
house, and where the electric lighting wires 
run outdoors. These condenser plugs work sat- 
isfactorily in nearly all instances, even in 
apartment houses, in connection with vacuum tube 
sets, but they do not work well as a rule with crystal 
receivers. Much experimental work is as yet to 
be done in this line, but the chances are that ten 
years from now, the serial for receiving purposes 
will be a thing of the past. 

Perhaps the greatest development will be the 
radio power transmission of the future. This is, of 
course, today, only a dream, but Nikola Tesla has 
demonstrated that it can be done, and it is interest- 
ing to note that this great savant's ideas are coming 
more and more to the front. Dr. Tesla contends 
that our radio conceptions are wrong from start to 
finish. He claims that it is not the radio waves that 
travel through the ether following the curvature of 
the earth, but rather currents that travel through the 
earth, and we seem to be coming to just this. If 
Tesla is right, power transmission by radio should 
be a simple thing. It will enable us to tap the earth 
at any point and receive our energy to light and heat 
our houses. Of course all this is in the future, but 
we are surely coming to it. 

Another new use for radio is sending pictures, 
photographs, etc., through the ether, and the author 
believes that he cannot do better than quote part of 



THE FUTURE OF RADIO 233 

his editorial from the November 1921 issue of 
Radio News. 

"Recently the signatures of General Foch and 
General Pershing were sent across the Atlantic by 
radio on the Belin apparatus. There is no good 
reason why the amateur cannot do the same thing 
for smaller distances at any time. 

"In the very near future, the amateur in New 
York will buy the first copy of a New York news- 
paper, wrap it around his cylinder, and send out a 
whole sheet by radio. A thousand miles away an- 
other amateur will have a receiving machine that 
will reproduce the printed page, type, pictures, and 
all in less than a half-hour. This is a thing impossible 
to do by ordinary wireless telegraphy, if every word 
must be transmitted. The radio picture transmis- 
sion solves all this. Thus, in time, a great piece of 
news 'breaking' in the city, will be sent broadcast by 
the enterprising amateur, who will send the entire 
front page of the newspaper, for instance, and the 
radio facsimile can then be exhibited in a distant 
town from 10 to 24 hours in advance of the receipt 
of the actual newspaper. 

"All this is not a mere dream, but it already 
has been accomplished today. It is up to the ama- 
teur to make the thing popular." 

To go still a step further, the author in a recent 
article in Science & Invention magazine pro- 
posed a radio system, which theoretically is 
sound. It is nothing else than Television by 



234 RADIO FOR ALL 

Radio. (Fig. 121). The fundamentals of this pro- 
posed scheme are correct, and there is little doubt 
that we will have radio television within a very few 
years on a scale that will be tremendous. The idea 
in short follows: 

At the Polo Grounds of New York, let us say, 
we have a radio transmitting station in a box-like 
affair of about three or four times the size of a 
movie camera. We have a box with a lens in front, 
the back of the camera being composed of a great 
number of photo-el ectric cells. These cells have the 
property of passing more or less electric current, 
depending upon how much light falls upon the cell. 
A strong light will pass much current through a 
cell, while a weak light will pass little current. By 
means of these cells, we influence a modulator vac- 
uum tube connected to the radio transmitter. This 
modulator sends out radio waves into space. If a 
strong light falls upon the electric cell, No. 1, we 
send out a radio wave of a certain intensity at a cer- 
tain wave length, let us say 500^ meters. At the 
receiving end, this wave is received and is passed 
through the regulation radio outfit and thence 
through a condenser, vacuum tube and audio- 
frequency transformer. This audio-frequency 
transformer operates a small magnet which in turn 
influences a pivoted diaphragm. This diaphragm 
has mounted upon it a strip mirror about y^- 
inch long and 1/16-inch wide. Normal and 
at rest, a light ray from a common source, let us say 



THE FUTUBE OF RADIO 



35 




236 RADIO FOR ALL 

an electric lamp, directs a single beam of light upon 
the diaphragm in such a manner that the light ray 
just misses the mirror. The least vibration of the 
diaphragm, however, will intercept the light ray and 
will reflect it upon a ground glass plate. It is evi- 
dent that the more the diaphragm vibrates, the 
more the light ray will vibrate back and forward 
upon the ground glass screen. 

If we now imagine at the sending end several 
hundred of the photo-electric cells and at the receiv- 
ing end a like number of vibrating mirrors, we can 
readily see how a picture sent out from the sender 
can be recomposed and reconstructed at the receiver. 
It must be understood that our photo-electric cell 
sends out its own wave-length. Thus, as mentioned 
before, photo-electric cell No. 1 sends out a wave 
length of 500y 2 meters. Photo-electric cell No. 
2 will send out a wave of 500>4 meters and so on. All 
these waves are sent out from the same aerial, 
and all the incoming waves are caught upon 
the same aerial, each wave operating its own 
electro-magnet and consequently the light beam. 
We can now see from this how our future 
audience will be able to witness a baseball game five 
hundred or five thousand miles distant, as if it were 
witnessing the game itself. It is, of course, under- 
stood that this transmission takes place instantan- 
eously, so we will be enabled in the future to view 
distant games or other important events at the time 
they are taking place. This differs from the movies 



THE FUTURE OF RADIO 237 

where we are not able to view the events at the time 
they take place, but always at a later date. In the 
future there will be the possibility of our seeing the 
President of the United States make an important 
speech, and we will be enabled to not only hear every 
word he utters, but see him in person as well. 

Of course, it goes without saying that the scheme 
here advanced will project the picture in black and 
white only. In other words, the picture will look 
just like a movie film with the sole difference that 
we are witnessing the event at the time it takes place. 

Here is an interesting feature of which few peo- 
ple are aware. Some months ago, in one of the 
writer's editorials he mentioned the fact that radio 
waves are eternal, as are light waves; they travel 
according to our present conception out into space 
at the rate of 186,000 miles a second. We see to- 
day the light waves shot off by some far away star, 
which light may have originated from that star per- 
haps 10,000 or 100,000 years ago. And those light 
rays are just coming down to us now. It is the 
same with radio waves. Any radio message, any 
broadcasted radio selection that is sent out on radio 
waves goes out into eternity never to return, never 
stopping, ever traveling onward. The thought is 
appalling that while you are listening to a famous 
operatic star, who is singing from some broadcasting 
station, her voice may be heard 100,000 years from 
now on some distant planet belonging to its own 
little solar system. 



238 RADIO FOR ALL 

For to believe that there is intelligence only on 
this earth is grotesque and foolish in the extreme. 
What this superior intelligence, listening to this 
broadcasted song will think of it 100,000 years 
hence, is difficult to imagine. But, there seems to 
be little doubt that this superior intelligence will 
smile at the idea of our feeble endeavors. This intel- 
ligence will probably view our attempts with the 
same amusement as we look upon children using 
a string telephone. 

At the time this volume is written, radio is just 
about twenty-five years old. If we have accom- 
plished such wonders in a quarter of a century, 
who dares say what will be accomplished in twenty- 
five or fifty years more. Our wildest and most im- 
possible prophesies will seem feeble. When we, 
therefore, say that one of the coming things is trans- 
porting solids through space, that is, send- 
ing a carload of coal from Pittsburgh to Paris 
within a few minutes, all by radio, and all by the 
invisible self-same waves, we will probably be laugh- 
ed at by our experts. The thing, however, is per- 
fectly feasible today, as we shoot solid particles 
through glass walls every time an X-ray picture is 
taken. X-rays are composed of solid particles which 
are just as solid as bricks or lumps of coal. When, 
therefore, we are asked what the future of radio is, 
we may say in one word, ANYTHING ! There seems 
to be nothing impossible that radio cannot accom- 
plish in the future: 




rporation, Westinghouse Photo 



The power plant at the radio broadcasting station WJZ, Newark, N. J. We see here five special 
vacuum tubes, each generating about 50 Watts power. This gives a total power of 250 Watts, or 
^Kilowatt. On top of the case we see the oscillation transformer which has the function of 
adjusting the wave length at which the broadcasting is accomplished, in this case 360 meters. 
I he waves emitted by this station have been heard several thousand miles away. 



CHAPTER XII 
RADIO ACT OF 1912 

MISCELLANEOUS RADIO INFORMATION 

LIST OF BROADCASTING STATIONS IN UNITED 

STATES AND CANADA 

TIME SIGNALS 

UNITED STATES AND POSSESSIONS 

The stations listed below send time daily for five minutes, starting 
at five minutes before the time set opposite each station. Each tick of 
a standard clock is transmitted as a dot, omitting the 29th second of 
each minute, the last five seconds of each of the first four minutes, 
and finally the last ten seconds of the last minute. A dash is sent at 
the time given opposite the station. 

11=55 AM 

9--5S P.M. 10" 20" 30" 40' 50 59* 



56' 
*< 



.;................, 



&. 



i ocee<t*e***o*******ooo oo 

59' 

^oooooooooo 

12 NOON 

OOOO 

^THIS DASH -3 DOTS 

Station CaH Wave-Length Time 

Annapolis, Md ....NSS 17,000 Arc Noon, 10.00 P.M. 75th 

meridian standard time. 

Arlington, Va NAA 2,650 Spark Noon, 10.00 P.M. 75th 

meridian standard time. 

Key West, Fla NAR 1,500 Spark Noon, 75th meridian 

standard time. 

New Orleans, La.* NAT 1,000 Spark Noon, 75th meridian 

standard time. 

Darien, C. Z NBA 10,110 Spark, 5.00 A.M. ; 1.00 P.M. 

75th meridian standard 
time. 
* Time signals not sent on Sundays and holidays. 

289 



240 



RADIO FOR ALL 



Station Call 

Honolulu NPM 

Cavite, Philippine Isl NPO 



.NPO 



.NPK 



Wave-Length Time 

800 Arc from 23,65 to 24,00 GMT. 
952 Spark from 02,55 to 03,00 GMT 
and from 13,55 to 14,00 
GMT. 

5,000 Arc from 01,55 to 02,00 and 
from 14,55 to 15,00 GMT. 
1,512 Spark Noon, 120th meridian, 

west, standard time. 

NPE 2,800 Spark, Noon, 120th meridian, 
west, standard time. 

San Francisco, Cal NPG 2,400 Spark Noon, 120th meridian, 

west, standard time. 

San Francisco, Cal NPG 4,800 Arc Noon, 120th meridian, 

west, standard time. 

Great Lakes, 111.* NAJ 1,512 Spark 11.00 A.M., 90th me- 
ridian standard time. 

Eureka, Cal.* NPW 2,000 Spark Noon, 120th meridian, 

west, standard time. 
7,000 Arc 5.00 A.M., 1.00 P.M., 75th 
meridian standard time. 
1,500 Spark 5.00 A.M., 1.00 P.M., 
75th meridian standard 
time. 
2,400 Spark Noon, 120th meridian, 

west, standard time. 
9,800 Arc Noon, 120th meridian 

standard time. 
NPM 11,200 Arc 180th meridian, mean 

noon. 

NPM 600 Spark 180th meridian, mean 
noon. 



Cavite, Philippine Isl. 
Pt. Arguello, Cal.* . . 
North Head, Wash.* 



Balboa, Panama NBA 

(undamped-Chopper) 
Colon, Panama NAX 



San Diego, Cal 

San Diego, Cal.* . . . 
Pearl Harbor, T. H.. 
Pearl Harbor, T. H.. 



.NPL 



.NPL 



SCHEDULE OF WEATHER REPORTS 

UXITED STATES AND POSSESSIONS 



Call 
Letter 



Broadcasting Hour 
(75th Meridian Time) 



Name of Station 

Arlington, Va. NAA 10.30 A.M., Noon, 10 P.M. 

Key West, Fla. NAR 10 P.M. 

Point Isabel, Tex NAY 12 Midnight 

Point Isabel, Tex NAY Noon, 7 P.M. 



Wave- 
Length 

2650 
1500 
2850 
2250 



*Time signals not sent on Sundays and holidays. 



RADIO ACT OF 1912 241 

Call Broadcasting Hour Wave- 
Name of Station Letter (75th Meridian Time) Length 

Great Lakes, 111.' NAJ Noon, 10 P.M. 1500 

San Juan, P. R.* NAU 10 A.M., 9 P.M., 600 Spark and 

5250 C.W. 
San Juan, P. R. NAU When issued and repeated at about 

4-hour intervals 2750 

Portland, Me NAB Noon, 8 P.M. 1620 

Boston, Mass NAD 11. A.M., 5 P.M. 2250 

New York, N. Y NAH 10.30 A.M., 5 P.M. 1832 

Philadelphia, Pa N A I 10.45 A.M., 5 P.M. 1948 

Baltimore, Md NBZ 10.80 A.M., 4 P.M. 700 

Norfolk, Va NAM 10.45 A.M., 4 P.M., 8 P.M. 1851 

Charleston, S. C., NAO 10.30 A.M., 6 P.M. 2250 

Savannah, Ga NEV 11 A.M., 6 P.M. 1813 

Jacksonville, Fla N F I 11 A.M., 6 P.M. 450 

St. Augustine, Fla NAP 11.30 A.M., 7 P.M. 1851 

Miami, Fla. NGE 11.30 A.M., 6 P.M. 1620 

St. Petersburg, Fla NGL 11.30 A.M., 7 P.M. 2700 

Pensacola, Fla, NAS 11.45 A.M., 6 P.M. 2250 

New Orleans, La. NAT 11 A.M., 5 P.M. 1832 

Galveston, Tex. NKB 11.30 A. M., 6 P.M. 1813 

Alpena, Mich NSM 10.45 A.M., 11.45 A.M., 

4.45 P.M., 7.45 P.M. 1200 

Buffalo, N. Y N N Z 10.45 A.M., 4.45 P.M. 1200 

Cleveland, Ohio NRH 11 A. M., 5.30 P.M. 1080 

Chicago, 111 NUR 11 A.M., 5.30 P.M. 1200 

Duluth, Minn. .NUX 10.45 A.M., 4.45 P.M. 2200 

Guantanamo, Cuba NAW When issued and repeated at 

about 4-hour intervals 2750 

Port au Prince, Haiti ....NSC When issued and repeated at 

about 4-hour intervals 2250 

St. Thomas, V. I. NBB When issued and repeated at 

about 4-hour intervals 1688 

St. Croix, V. I NNI When issued and repeated at 

about 4-hour intervals 450 

San Francisco, Cal. ..... .NPH Noon, 10 P.M., 120th Men 950 

North Head, Wash NPE Noon, 10 P.M., 120th Mer. 950 

San Diego, Cal NPL Noon, 10 P.M., 120th Mer. 950 

* Distribution is made from this station from April 15th to De- 
cember 20th. 

"Distribution is made from this station from June to November, 
inclusive. 
16 



242 



RADIO FOR ALL 



NOTE: Noon transmission for Arlington and Great Lakes are 
storm warnings, and 10 A.M. and when " issued transmission " for 
San Juan are hurricane warnings. 

All afternoon and evening transmission listed above, beginning 
with Portland, Maine, and ending with St. Croix, V. I., are storm 
or hurricane warnings and advices. 

ABBREVIATIONS USED IN WEATHER REPORTS 



ATLANTIC COAST 

Sydney, N. S S 

Nantucket, Mass T 

Breakwater, Delaware DB 

Hatteras, N. C H 

Charleston, S. C C 

Key West, Fla. K 

Pensacola, Fla P 

Bermuda B 

St. Johns, N. F J 

New York, N. Y NY 

Lynchburg, Va LB 

Cape Henry, Va. CH 

Asheville, N. C AV 

Atlanta, Ga AT 

Jacksonville, Fla. JA 

Tampa, Fla TA 

Mobile, Ala MO 

Burrwood, La BW 

Galveston, Tex GV 

Brownsville, Tex BV 

Fort Worth, Tex FW 

Corpus Christi, Tex GV 

Kingston, Jamaica KN 

Turks Island TI 

Havana, Cuba HA 

Guantanamo Bay GO 

Swan Island SI 

San Juan, P. R SJ 

St. Thomas, Virgin Isls. . . . . .ST 

Basseterre, St. Kitts BT 

Roseau, Dominican Republic. .RS 



Bridgetown, Barbadoes BB 

Santo Domingo, Dominican 

Republic SD 

Puerto Plata, Dominican 

Republic SL 

Castries, St. Lucia LU 

Willemstadt, Curacao W 

Port of Spain, Trinidad PS 

GREAT LAKES 

Duluth, Minn DU 

Marquette, Mich M 

Sault Ste. Marie, Mich U 

Green Bay, Mich G 

Chicago, 111 CH 

Alpena, Mich L 

Detroit, Mich D 

Cleveland, Ohio V 

Buffalo, N. Y F 

Grand Haven, Mich GH 

Father Point, Can FP 

Montreal, Canada ML 

St. Louis, Mo SL 

Little Rock, Ark .LR 

Nashville, Tenn N V 

Cincinnati, Ohio CN 

PACIFIC COAST 

Tatoosh, Wash T 

North Head, Wash NH 

Eureka, Cal E 

San Francisco, Cal SF 

San Diego, Cal SD 



RADIO ACT OF 1912 243 

ARLINGTON WEATHER REPORT. 2,500 METERS N.A.A. 

Sample Report: QSTdeNAA, USWB, SolOSl To2261 DB 
0251 H 00844 C 01261 K 004410 P 01243. 

EXPLAKATIOK 

QST General call 

de From 

NAA Arlington Station 
USWB U. S. Weather Bureau 

S Sydney, Nova Scotia 
"010" 30.10 inches, Barometer 
8 __ wind Northwest 
"1" Light air 

T Nantucket, R. I. 
"022" 30.22 inches, Barometer 
6" _ Southwest wind 
"1" Light air 

DB Delaware Breakwater 
"020" 30.20 inches, Barometer 
"5" South wind. 
"1" Light air 

H Cape Hatteras 
008" 30.08 inches, Barometer 
"4" Southeast wind 
"4" Moderate breeze 

C Charleston, S. C. 
"012" 30.12 inches, Barometer 
6" Southwest wind 
"1" Light air 

K Key West, Fla. 
"004" 30.04 inches, Barometer 

"4" Southeast wind 
"10" Whole gale. 

P Pensacola, Fla. 
012" 30.12 inches, Barometer 
"4" Southeast wind 
3 _ Gentle breezes. 



44 



RADIO FOR ALL 

BEAUFORT WIND INTENSITY SCALE 




sw 



SE 



Statute Miles Pei 

Calm 08 

1 Light Air 8 

2 Light Breezes 18 

3 Gentle Breezes 18 

4 Moderate Breezes 23 

5 Fresh Breezes 28 

6 Strong Breezes 34 

7 Moderate Gale 40 

8 Fresh Gale 48 

9 Strong Gale 56 

10 Whole Gale 65 

11 Storm 75 

12 Hurricane 90 

Statute Miles per Hour: 1.15 Nautical M.P.H. 

U. S. STATIONS SENDING MARKET REPORTS 



Name of Station 
Washington, D. C. . 
Hazelhurst, N. Y. 
Bellefonte, Pa. 
Cincinnati, Ohio .. 



CaH 
Letters 

wwx 
wwu 

WWQ 
KDQC 



St. Louis, Mo KDEL 



Wave-Lengths 
Call- Work Broadcasting Hours 

3800 3850 7.30 and 8.00 P.M. 

3800 3400 

3800 3450 

3800 3600 9.00 and 11.00 A.M., 12.00 

3000 Noon, 7.30 and 8 P.M. 

3800 3675 9.15, 11.30 A.M., 12.30, 

3.30,8.15 and 8.45 P.M. 



RADIO ACT OF 1912 



245 



Name of Station 
Omaha, Neb 



North Platte, Neb... 
Rock Springs, Wyo.. . 

Cheyenne, Wyo 

Salt Lake City, Utah. 
Elko, Nevada 



Call Wave-Lengths 

Letters Call- Work Broadcasting Hours 

KDEF 2900 4167 9.00, 11.00 A.M., 12.00 
Noon, 2.00, 3.00, 5.30, 
8.00 and 8.30 P.M. 

KDHM 2900 3400 9.30 A.M., 12.00 Noon, 
6.00 and 9.00 P.M. 

KDHN 2900 3200 9.00 A.M., 12.00 Noon, 
6.30,8.00 and 8.30 P.M. 

KDEG 2900 3740 

KDEH 2200 3600 

KDEJ 2200 3400 



8.30 A.M., 12.00 Noon, 

4.00 P.M. 
Reno, Nevada. KDEK 2200 2800 9.00 A.M., and 1.00 P.M. 

Stations are also now being installed at Bryan, Ohio, and Iowa 
City, Iowa. 

The above stations are all 2-KW Federal arc transmitters and are 
not only used for furnishing communications to the Air Mail Service, 
but they are also utilized in broadcasting agricultural market reports, 
and weather reports. Broadcasts are now being transmitted from 
the stations as shown above at the hours listed. 



Can 
NAA 
NAR 
NAX 
NPG 
KHK 
NAH 

NPL 
BZM 
VCU 
BZL 
BZN 
BYZ 

OAZ 


PRESS SCHEDULES C 

Wave 

Station 

Washington, D. C 
Key West, Fla. 


)F SPJ 

-Length 
Meters 
. 2650 
1500 
2400 
600 
600 
1500 

2400 
1500 
. 1500 
. 1300 
4300 
2650 

. 1500 


^RK STATIONS 

Time 
10 P.M., 75th meridian 
10 P.M., 75th meridian 
10 P.M., 75th meridian 
1.15 A.M., local time 
11.30 P.M., local time 
9.00 P.M., 5 A.M., local 
time 

7.30 A.M. (GMT)* 
8.00 A.M. (GMT) 
6.00 A.M. (GMT) 
3.30 A.M. (GMT) 
9.00 A.M., 7.00 P.M, 
(GMT) 
2.00 A.M., 3.30 P.M. 
(GMT) 


Colon, Panama 


San Francisco, Cal 
Honolulu, Hawaii 


New York, N. Y 


San Diego, Cal 


St. Johns, N. F., , 


Barrington Passage, N. F. 
Demerara, British Guiana. 
Falklands 


Malta (Rinella) . 


San Cristobal, Peru 



* Greenwich (England) mean time. 



246 



RADIO FOR ALL 



WaveLewfth 


Call 


Station 


Meters 


Time 


BXY 


Hong Kong, China 


. 2000 


9.45 P.M. (GMT) 


BXW 


Singapore 


2000 


9.15 P.M. (GMT) 


BZE 


Matara, Ceylon 


2000 


8.45 P.M. (GMT) 


BZF 


Aden, British Somaliland. 


. 2000 


7.30 P.M. (GMT) 


BZH 


Seychelles 


2000 


9.45 P.M. (GMT) 


BZG 


Mauritius 


2000 


10.30 P.M. (GMT) 


BZI 


Durban, South Africa 


. 2000 


3.15 P.M. (GMT) 


VMG 


Apia, Samoa 


, 2000 


11.30 A.M. (GMT) 


VLA 


Awanui 


. 2000 


7.15 A.M. (GMT) 


VLB 


Awarua, Australia 


. 2000 


10.45 A.M. (GMT) 


VID 


Darwin, Australia 


. 850 


6.30 P.M. (GMT) 


VKT 


Naura, Australia 


. 2200 


7.00 P.M. (GMT) 


VIP 


Perth, Australia 


. 1500 


4.30P.M. (GMT) 


VJZ 


Rabaul, Australia 


. 2900 


6.00 P.M. (GMT) 


VIS 


Sydney, Australia 


. 2000 


3.30 P.M. (GMT) 


VIT 


Tounsville, Australia 


. 1000 


4.30 P.M. (GMT) 


VIF 


Woodlark Isl., Australia. 


. 1000 


5.00 P.M. (GMT) 


UA 


Nantes, France 


2400 


3.30 A.M., 3.45 








(GMT) 


FL 


Paris, France 


2500 


3.00 P.M. (GMT) 


YN 


Lyons, France 


5000 


8.00 A.M. (GMT) 



P.M. 



RADIO CODE ABBREVIATIONS 



247 



LIST OF ABBREVIATIONS USED IN RADIO CODE 



ABBREVIA- 
TION QUESTION 
PRB Do you wish to communi- 
cate by means of the Inter- 
national Signal Code?... 

QRA What ship or coast station 
is that 5 


ANSWER OB NOTICE 

I wish to communicate by means 
of the International Signal 
Code. 

This is 


QRB What is your distance? .. 
QRC What is your true bearing? 
QRD Where are you bound for?. 
QRF Where are you bound from? 
QRG What line do you belong to? 
QRH What is your wave-length in 
meters? 


My distance is .... 
My true bearing is . . degrees. 
I am bound for 
I am bound from 
I belong to the line. 

My wave-length is .... meters. 


QRJ How many words have you 
to send ? 


I have .... words to send. 


QRK How do you receive me? . . 
QRL Are you receiving badly? 
Shall I send 20 ... . 
for adjustment? 

QRM Are you being interfered 
with? 
QRN Are the atmospherics 
strono"? 


I am receiving well. 

I am receiving badly. Please 
send 20 ... . 
for adjustment. 

I am being interfered with. 


QRO Shall I increase power? .. 
QRP Shall I decrease power? 
QRQ Shall I send faster? 
QRS Shall I send slower 5 


Increase power. 
Decrease power. 
Send faster. 


QRT Shall I stop sending? 
QRU Have you anything for me? 
QRV Are you ready? 


Stop sending. 
I have nothing for you. 


QRW Are you busy? 


I am busy (or 4 I am busy with 


QRX Shall I stand by? 


. . . ). Please do not interfere. 
Stand by. I will call you when 
required. 



248 



RADIO FOR ALL 



ABBREVIA- 

TION QUESTION 

QRY When will be my turn?. 
QRZ Are my signals weak? 
QSA Are my signals strong? 



( Is my tone bad?.. 
^ \ Is my spark bad?. 



QSC Is my spacing bad? ........ 

QSD What is your time? ........ 

QSF Is transmission to be in al- 
ternate order or in series? 



QSG 
QSH 



QSJ What rate shall I collect 
for ? 

QSK Is the last radiogram can- 
celled? 

QSL Did you get my receipt ? 

QSM What is your true course? 

QSN Are you in communication 
with land? 

QSO Are you in communication 
with any ship or station; 
(or: with )? 

QSP Shall I inform .... that you 
are calling him? 

QSQ Is .... calling me? 

QSR Will you forward the radio- 
gram? 

QST Have you received the gen- 
eral call? 

QSU Please call me when you 
have finished (or: at .. 
o'clock) 



ANSWER OR NOTICE 

Your turn will be No 

Your signals are weak. 
Your signals are strong. 
The tone is bad. 
The spark is bad. 
Your spacing is bad. 

My time is 

Transmission will be in alter- 
nate order. 

Transmission will be in series 

of 5 messages. 
Transmission will be in series 

of 10 messages. 

Collect 

The last radiogram is cancelled. 

Please acknowledge. 

My true course is . . degrees. 

I am not in communication with 
land. 



I am in communication with 
(through . . . .) 

Inform that I am calling 

him. 
You are being called by 

I will forward the radiogram. 
General call to all stations. 

Will call when I have finished. 



RADIO ACT OF 1912 



249 



ABBREVIA- 
TION QUESTION 
QSV* Is public correspondence 
being handled? 



QSW Shall I increase my spark 

frequency? 

QSX Shall I decrease my spark 

frequency? 

QSY Shall I send on a wave- 
' length of .... meters ? ... 



QSZ 

QTA 
QTB 



QTC Have you anything for me? 
QTE What is my true bearing? 
QTF What is my position? 



ANSWER OR NOTICE 

Public correspondence is being 
handled. Please do not 
interfere. 

Increase your spark frequency. 
Decrease your spark frequency. 

Let us change to the wave- 
length of . . meters. 

Send each word twice. I have 
difficulty in receiving you. 

Repeat the last radiogram. 

Send initials of each word to 
confirm check. 

I have .... msgs for you (or: I 
have something for you.) 

Your true bearing is .... de- 
grees from 

Your position is latitude, 

longitude. 



* Public correspondence is any radio work, official or private, 
handled on commercial wave-lengths. 

When an abbreviation is followed by a mark of interrogation, it 
refers to the question indicated for that abbreviation. 

CAPACITY OF CONDENSERS 

To find the capacity of condensers use the following formula: 
AXK 



C = 



4 X 3.1416 X T X 900,000 



C = Capacity in microfarads. 

A = Area in square centimeters of one set of plates or surface. 

K = Dielectric constant or specific inductive capacity of the 

dielectric used. (Given under " Dielectric Constants.") 
T = Thickness of the dielectric between the plates, surfaces 

measured in centimeters. 



250 RADIO FOR ALL 

FORMULAE 

CAPACITY. 
Capacity of two plates: 

2248 X K X A 
C = 



T X 10* 

C is capacity in microfarads. 
K is dielectric constant See table. 
A is area of plates in square inches. 
T is thickness of dielectric in inches. 



Capacity of condensers in parallel: 



Capacity of condensers in series: 

11111 

= + + + etc. 
C Ci C, C, C 

Capacity necessary for any transformer: 

_ KW X 10 g 

: E'Xf 

C is capacity in microfarads. 
KW is killowatts of power. 
E is secondary voltage. 
f is frequency of spark discharge. 

INDUCTANCE. 

Inductance of single layer round coil (solenoid) : 
0.03948 X A* XN* 





b 








Ratio of J* 11 ^ 
Diameter 


L 


= inductance in cm. 


1/10 


A 


= radius of coil 


1/4 


X 


= number of turns 


1/2 


b 


= length of coil 


3/4 


K 


= is a constant See 


table. 1 






3/2 






2 






3 






4 






5 



K" 

"K" 

0.9588 
0.9016 
0.8181 
0.7478 
0.6884 
0.5950 
0.5255 
0.4292 
0.3654 
0.3198 



RADIO ACT OP 1912 251 

TABLE OF "L" SERIAL DIMENSIONS 



Height 
Above 
Ground 
(Feet) 


No. of 
Strands 


Spacing 
Between 
Strands 
(Feet) 


Length 

Strands 
(Feet) 


Approx. Approx. Wave- 
Daylight Length with 
Reo. Maximum Length 
Range Aerial Given 
(Miles) (Metres) 


30 


4 


2% 


60-80 


75-125 151 


40 


4 


2y 2 -3 


80-90 


100-150 165 


50 


4- 


3 


80-90 


125-175 178 


75 


4-6 


3 


80-100 


150-300 240 



WAVE-LENGTHS OF 2ERIALS 

To calculate the approximate natural wave-length of an aerial, 
the total length of the aerial in feet should be multiplied by the 
factor 4.5. This gives the natural wave-length of the aerial in feet. 
This result may be divided by 3.28 to obtain the wave-length 
in meters. 

Let us take, for example, a flat-top aerial with a length of 100 feet, 
connected to a lead-in wire at one end 100 feet long. Then 100 feet 
plus 100 feet gives 200 feet, and this multiplied by 4.5 gives 900 feet 
as the natural wave-length. Divided by 3.28, we have 274 meters 
wave-length. 

If the above antenna happened to be connected "T" type, then the 
effective radiating length of same would be 

1^0 plus 100 = 160 feet. 

This value, multiplied by 4.5 gives 675 feet wave-length, which, 
divided by 3.28, gives 206 meters. 

LOOP ANTENNA 

Range of 4 Ft. Square Loop Aerial 

Turin Best Wave-Length Meters 

3 250 200-350 

4 300 250-400 
6 350 300-800 

10 600 350-1000 

20 1200 900-1800 

Range of 6 Ft. Square Loop Aerial 

2 220 180-400 

6 600 400-900 

10 700 600-1200 

20 1400 1000-2000 



253 RADIO FOR ALL 

Spacing for Loops 
Size of Loop in Feet Spacing i n Inches 

3 1/8 

4 1/4 
6 7/16 
8 9/16 

10 3/4 

12 15/16 

WAVE-LENGTHS AND FREQUENCIES 
W.L. Wave-Lengths in Meters. F. Number of Oscillations per 
Second. 

WL. F. 

50 6,000,000 

100 3,000,000 

150 2,000,000 

200 1,500,000 

250 1,200,000 

800 1,000,000 

350 857,100 

400 750,000 

450 666,700 

500 600,000 

650 645,400 

600 600,000 

700 428,600 

800 375,000 

900 333,300 

1000 300,000 

1100 272,730 

1200 250,000 

1300 230,760 

1400 214^80 

1500 200,000 

1600 187,500 

1700 176,460 

1800 166,670 

1900 157,890 

2000 150,000 

2100 142,850 

2200 136,360 

2300 130,430 

2400 125,000 



RADIO ACT OF 1912 253 

W.L. F. 

2500 120,000 

2600 115,380 

2700 111,110 

2800 107,140 

2900 103,450 

3000 100,000 

4000 75,000 

5000 60,000 

6000 50,000 

7000 41,800 

8000 37,500 

9000 33,300 

10000 30,000 

11000 27^00 

12000 25,000 

13000 23,100 

14000 21,400 

15000 20,000 

16000 18,750 

Explanation: A wave of 350 meters will oscillate (vibrate back 
and forth) at the rate of 857,100 times in every second. 

ENGLISH AND METRIC EQUIVALENTS 
1 metre = 39.37 inches 
1 cm. = 0.3937 inches 
1 foot = 30.48 cms. or 0.3048 meters. 
1 inch = 2.54 cms. 
1 meter = 100 cms. 

DIELECTRIC CONSTANTS "K" 

Air 1. Mirror Glass 6.00 

Compressed Air 1.004 Common Glass 3.5 

Crown Glass 6.96 Mica 8.0 

Flint Glass 7.00 Paper 2.5 

Plate Glass 8.45 Paraffin 2.25 

Mica, therefore, is the highest (best) insulator; it is eight times 
better than air. 



254 RADIO FOR AIX 

ELECTRICAL UNITS 

RESISTANCE. 

The unit of resistance is the ohm. Very large resistances, as for 
instance, insulation resistances, are more conveniently reckoned in 
Meg-Ohms and very small resistances in Micro-ohms. 
1 Meg-ohm = 106 ohms = 1 million ohms. 
1 Micro-ohm = 10- 6 ohms = 1 millionth of an ohm. 

CURRENT. 

The unit of current is the ampere, small currents being reckoned 
in Milli-amperes or in Micro-amperes. 

1 Milli-ampere = 10- 3 ampere = 1 thousandth of an ampere. 
1 Micro-ampere = 10- 6 ampere = 1 millionth of an ampere. 

ELECTRO-MOTIVE-FORCE. 

The unit of E.M.F. is the volt, small potential differences being 
reckoned in Milli-volts or in Micro-volts. 

1 Milli-volt = 10-3 volts = 1 thousandth of a volt. 

1 Micro-volt = 10-e volts = 1 millionth of a volt. 
QUANTITY. 

The unit of quantity is the coulomb, which equals the quantity 
of electricity conveyed by a current of one ampere flowing for 
one second. 

ENERGY. 

The unit of electrical energy is the joule. 
POWER. 

The unit of power is the watt, large powers are best reckoned in 
Kilo-watts and very small powers in Micro-watts. 

1 Kilo-watt = 10 3 watts = 1 thousand watts. 

1 Micro-watt = 10- watt = 1 millionth of a watt. 
746 watts = 1 H.P. 

CAPACITY. 

The unit of capacity is the Farad, smaller units being the micro- 
farad and the centimeter. 

1 Micro-farad = 10-' farads = 1 millionth of a farad. 

900,000 cms = 1 micro-farad. 

1 jar = 1,000 cms. 

1 Billi-farad = 900 cms. 

INDUCTANCE. 

The unit of inductance is the henry, smaller units being the milli- 
henry, the micro-henry and the centimeter. 

1 Milli-henry = 10-* henry = 1 thousandth of a henry. 

1 Micro-henry = 10-6 henry = 1 millionth of a henry. 

1,000 cms. = 1 micro-henry. 

1 Coil = 25,000 cms. 



RADIO ACT OF 1912 



255 






ililililllillill 












ggiSSSgS 

'S223JSS3S 



?s=s< 



52; 



11?' 



256 



RADIO FOR ALL 



FEET PER POUND OF INSULATED 


MAGNET WIRE 


Number 


Single 


Double 


Single 


Double ( 


-_,_1J 


B. oiS. 




Cotton 




Silk 


rfUameieu 


ttauge 












20 


311 


298 


319 


812 


820 


21 


389 


370 


403 


889 


404 


22 


488 


461 


503 


493 


509 


23 


612 


584 


636 


631 


642 


24 


762 


745 


800 


779 


810 


25 


957 


903 


1005 


966 


1019 


26 


1192 


1118 


1265 


1202 


1286 


27 


1488 


1422 


1590 


1543 


1620 


28 


1852 


1759 


1972 


1917 


2042 


29 


2375 


2207 


2570 


2485 


2570 


30 


2860 


2534 


3145 


2909 


3240 


31 


3800 


2768 


3943 


8683 


4082 


32 


4375 


3737 


4950 


4654 


5132 


33 


5390 


4697 


6180 


5689 


6445 


34 


6500 


6168 


7740 


7111 


8093 


35 


8050 


6737 


9600 


8534 


10197 


36 


9820 


7877 


12000 


10039 


12813 


37 


11860 


9309 


15000 


10666 


16110 


38 


14300 


10636 


18660 


14222 


20274 


39 


17130 


11907 


23150 


16516 


25519 


40 


21590 


14222 


28700 


21833 


32107 




TABLE 


OF INSULATED MAGNET WIRE 


Size 


Turns per Linear Inch 


B. &S. 
Gauge 


Enameled 


Cottai 


Double 
Cotton 


Single 
Silk 


Double 

Silk 


20 


29 


25 


23 


27 


26 


21 


32 


28 


26 


31 


29 


22 


36 


31 


28 


34 


32 


23 


41 


34 


31 


38 


36 


24 


45 


37 


33 


42 


39 


25 


51 


41 


36 


47 


43 


26 


56 


45 


39 


52 


46 


27 


64 


49 


42 


57 


52 


28 


71 


54 


45 


, 63 


56 


29 


79 


58 


48 


70 


62 


30 


88 


64 


57 


77 


67 


31 


100 


69 


58 


85 


72 


32 


112 


75 


60 


93 


78 


38 


184 


81 


64 


102 


84 



RADIO ACT OP 1912 257 



Size 




Turns per Linear Inch 




B. &S. 




Single Double 


Single Double 


Gauge 


Enameled 


Cotton Cotton 


Silk Silk 


34 


140 


87 68 


112 91 


35 


156 


94 73 


120 97 


36 


173 


101 78 


130 104 


37 


201 


108 84 


141 110 


38 


225 


115 89 


151 117 


39 


256 


122 95 


163 123 


40 


288 


130 102 


178 129 


DOUBLE 


COTTON-COVERED MAGNET WIRE 




Size 


Size 






B. &S. 


No. Turns per B. & S. 


No. Turns per 




Gauge 


Linear Inch Gauge 


Linear Inch 




0000 


1.70 7 


6.08 




000 


2.00 8 


6.80 




00 


2.32 9 


7.64 







2.65 10 


8.51 




1 


2.99 11 


9.56 




2 


3.36 12 


10.60 




3 


3.80 13 


11.88 




4 


4.28 14 


13.10 




5 


4.83 15 


14.68 




6 


5.44 16 


16.35 






TUNING COIL DATA 




No. of Wire 
B. & S. Gauge 


Diameter of 
Core in Inchn 


B s? . 
.S*o "ft o^j i^' to v'o.*' 

a! \& ?3i M 

IRS J*| tit yj 


S* *8 B 

![! i|| 
*$ JSj 


26 


2 in. 


30 37 58 .. 


.... 


28 


2 in. 


38 46 73 


.... 


24 


3 in. 


36 44 46 





*26 


Sin. 


46 56 58 34 


4 in. 700 


*24 


4 in. 


48 59 46 32 


Sin. 800 


22 


Sin. 


49 60 37 30 


6 in. 1000 


*22 


6 in. 


58 70 37 30 


6 in. 1200 


20 


7 in. 


55 67 30 




20 


8 in. 


63 77 30 


.... 


NOTE To 


find the wave-length in meters of any tuning coil, mul- 


tiply 


its length 


in inches by length in meters per 


inch of winding. 



* Indicates windings suitable for loose coupler primaries. 
17 



358 RADIO FOR ALL 

The data in this table were compiled for WINDINGS OF EN- 
AMELED WIRE ONLY. 

Wave-length in meters in above table equals length of wire on 
tuning coil in meters multiplied by 4 (not for couplers). 

VARIOCOUPLER VALUES 

With a Secondary of 2% inches in diameter, shunted by .0005 
m. f. Condenser, the following wave-lengths are obtainable: 

10 turns 80 to 220 meters 

20 turns 120 to 350 meters 

30 turns 150 to 420 meters 

40 turns 175 to 550 meters 

THE RADIO LAW OF 1912 

An Act to regulate radio communication, approved August 13, 1912. 
Be it enacted by the Senate and House of Repretentativet of the 
United Statet of America in Congrett attembled, That a person, com- 
pany, or corporation within the jurisdiction of the United States shall 
not use or operate any apparatus for radio communication as a means 
of commercial intercourse among the several States or with foreign 
nations, or upon any vessel of the United States engaged in interstate 
or foreign commerce, or for the transmission of radiograms or signals 
the effect of which extends beyond the jurisdiction of the State or 
Territory in which the same are made, or where interference would be 
caused thereby with the receipt of messages or signals from beyond 
the jurisdiction of the said State or Territory, except under and in 
accordance with a license, revocable for cause, in that behalf granted 
by the Secretary of Commerce upon application therefor; but noth- 
ing in this Act shall be construed to apply to the transmission and 
exchange of radiograms or signals between points situated in the same 
State: Provided, That the effect thereof shall not extend beyond the 
jurisdiction of the said State or interfere with the reception of radio- 
grams or signals from beyond said jurisdiction; and a license shall 
not be required for the transmission or exchange of radiograms or 
signals by or on behalf of the Government of the United States, but 
every Government station on land or sea shall have special call letters 
designated and published in the list of radio stations of the United 
States by the Department of Commerce. Any person, company or 
corporation that shall use or operate any apparatus for radio com- 
munication in violation of this section, or knowingly aid or abet an- 
other person, company, or corporation in so doing, shall be deemed 
guilty of a misdemeanor, and on conviction thereof shall be punished 
by a fine not exceeding five hundred dollars, and the apparatus or 



RADIO ACT OF 1912 259 

device so unlawfully used and operated may be adjudged forfeited to 
the United States. 

SEC. 2. That every such license shall be in such form as the Secre- 
tary of Commerce shall determine and shall contain the restrictions, 
pursuant to this Act, on and subject to which the license is granted; 
that every such license shall be issued only to citizens of the United 
States or Porto Rico or to a company incorporated under the laws 
of some State or Territory or of the United States or Porto Rico, and 
shall specify the ownership and location of the station in which said 
apparatus shall be used and other particulars for its identification 
and to enable its range to be estimated ; shall state the purpose of the 
station, and, in case of a station in actual operation at the date of 
passage of this Act, shall contain the statement that satisfactory proof 
has been furnished that it was actually operating on the above- 
mentioned date; shall state the wave-length or the wave-lengths 
authorized for use by the station for the prevention of interference 
and the hours for which the station is licensed for work; and shall 
not be construed to authorize the use of any apparatus for radio 
communication in any other station than that specified. Every such 
license shall be subject to the regulations contained herein, and such 
regulations as may be established from time to time by authority of 
this Act or subsequent Acts and treaties of the United States. Every 
license shall provide that the President of the United States in time of 
war or public peril or disaster may cause the closing of any station 
for radio communication and the removal therefrom of all radio 
apparatus, or may authorize the use or control of any such station or 
apparatus by any department of the Government, upon just com- 
pensation to the owners. 

SEC. 3. That every such apparatus shall at all times while in use 
and operation as aforesaid be in charge or under the supervision of 
a person or persons licensed for that purpose by the Secretary of 
Commerce. Every person so licensed who in the operation of any 
radio apparatus shall fail to observe and obey regulations contained 
in or made pursuant to this Act or subsequent Acts or treaties of 
the United States, or any one of them, or who shall fail to enforce 
obedience thereto by an unlicensed person while serving under his 
supervision, in addition to the punishments and penalties herein pre- 
scribed, may suffer the suspension of the said license for a period to 
be fixed by the Secretary of Commerce not exceeding one year. It 
shall be unlawful to employ any unlicensed person or for any un- 
licensed person to serve in charge or in supervision of the use and 
operation of such apparatus, and any person violating this provision 



260 RADIO FOR ALL 

shall be guilty of a misdemeanor, and on conviction thereof shall be 
punished by a fine of not more than one hundred dollars or imprison- 
ment for not more than two months, or both, in the discretion of 
the court, for each and every such offense: Provided, That in case of 
emergency the Secretary of Commerce may authorize a collector of 
customs to issue a temporary permit, in lieu of a license, to the 
operator on a vessel subject to the radio ship Act of June twenty- 
fourth, nineteen hundred and ten. 

SEC. 4. That for the purpose of preventing or minimizing inter- 
ference with communication between stations in which such apparatus 
is operated, to facilitate radio communication, and to further the 
prompt receipt of distress signals, said private and commercial 
stations shall be subject to the regulations of this section. These regu- 
lations shall be enforced by the Secretary of Commerce through the 
collectors of customs and other officers of the Government as other 
regulations herein provided for. 

The Secretary of Commerce may, in his discretion, waive the pro- 
visions of any or all of these regulations when no interference of the 
character above mentioned can ensue. 

The Secretary of Commerce may grant special temporary licenses 
to stations actually engaged in conducting experiments for the de- 
velopment of the science of radio communication, or the apparatus 
pertaining thereto, to carry on special tests, using any amount of 
power or any wave-lengths, at such hours and under such conditions 
as will insure the least interference with the sending or receipt of com- 
mercial or Government radiograms, of distress signals and radio- 
grams, or with the work of other stations. 

In these regulations the naval and military stations shall be under- 
stood to be stations on land. 

REGULATIONS 

XOKMAL WAVE-LEXGTH 

First. Every station shall be required to designate a certain 
definite wave-length as the normal sending and receiving wave-length 
of the station. This wave-length shall not exceed six hundred meters 
or it shall exceed one thousand six hundred meters. Every coastal 
station open to general public service shall at all times be ready to 
receive messages of such wave-lengths as are required by the Berlin 
convention. Every ship station, except as hereinafter provided, and 
every coast station open to general public service shall be prepared to 
use two sending wave-lengths, one of three hundred meters and one 
of six hundred meters, as required by the international convention in 



RADIO ACT OP 1912 261 

force: Provided, That the Secretary of Commerce may, in his dis- 
cretion, change the limit of wave-length reservation made by regula- 
tions first and second to accord with any international agreement to 
which the United States is a party. 

OTHER WAVE-LENGTHS 

Second. In addition to the normal sending wave-length all stations, 
except as provided hereinafter in these regulations, may use other 
sending wave-lengths: Provided, That they do not exceed six hundred 
meters or that they do exceed one thousand six hundred meters: 
Provided further, That the character of the waves emitted conforms 
to the requirements of regulations third and fourth following. 

USE OF A "PURE WAVE" 

Third. At all stations if the sending apparatus, to be referred to 
hereinafter as the " transmitter," is of such a character that the 
energy is radiated in two or more wave-lengths, more or less sharply 
defined, as indicated by a sensitive wave meter, the energy in no one 
of the lesser waves shall exceed ten per centum of that in the greatest. 

USE OF A " SHARP WAVE " 

Fourth. At all stations the logarithmic decrement per complete 
oscillation in the wave trains emitted by the transmitter shall not 
exceed two-tenths, except when sending distress signals or signals 
and messages relating thereto. 

USE OF " STANDARD DISTRESS WAVE " 

Fifth. Every station on shipboard shall be prepared to send dis- 
tress calls on the normal wave-length designated by the international 
convention in force, except on vessels of small tonnage unable to have 
plants insuring that wave-length. 

SIGNAL OF DISTRESS 

Sixth. The distress call used shall be the international signal of 
distress ... - ... 

USE OF " BROAD INTERFERING WAVE " FOR DISTRESS SIGNALS 

Seventh. When sending distress signals, the transmitter of a station 
on shipboard may be tuned in such a manner as to create a maximum 
of interference with a maximum of radiation. 

DISTANCE REQUIREMENT FOR DISTRESS SIGNALS 

Eighth. Every station on shipboard, wherever practicable, shall be 
prepared to send distress signals of the character specified in regu- 
lations fifth and sixth with sufficient power to enable them to be 



263 RADIO FOR ALL 

received by day over sea a distance of one hundred nautical miles by 
a shipboard station equipped with apparatus for both sending and 
receiving equal in all essential particulars to that of the station 
first mentioned. 

"BIGHT or WAY" FOR DISTRESS SIGNALS 

Ninth. All stations are required to give absolute priority to signals 
and radiograms relating to ships in distress; to cease all sending on 
hearing a distress signal; and except when engaged in answering or 
aiding the ship in distress, to refrain from sending until all signals and 
radiograms relating thereto are completed. 

REDUCED POWER FOR SHIPS NEAR A GOVERKMEKT STATION 

Tenth. No station on shipboard, when within fifteen nautical miles 
of a naval or military station, shall use a transformer input exceeding 
one kilowatt, nor, when within five nautical miles of such a station, a 
transformer input exceeding one-half kilowatt, except for sending 
signals of distress, or signals or radiograms relating thereto. 

INTERCOMMUNICATION 

Eleventh. Each shore station open to general public service be- 
tween the coast and vessels at sea shall be bound to exchange radio- 
grams with any similar shore station and with any ship station with- 
out distinction of the radio systems adopted by such stations, 
respectively, and each station on shipboard shall be bound to exchange 
radiograms with any other station on shipboard without distinction of 
the radio systems adopted by each station, respectively. 

It shall be the duty of each shore station, during the hours it is 
in operation, to listen in at intervals of not less than fifteen minutes 
and for a period not less than two minutes, with the receiver tuned to 
receive messages of three hundred meter wave-lengths. 

DIVISION OF TIME 

Twelfth. At important seaports and at all other places where naval 
or military and private or commercial shore stations operate in such 
close proximity that interference with the work of naval and military 
stations can not be avoided by the enforcement of the regulations 
contained in the foregoing regulations concerning wave-lengths and 
character of signals emitted, such private or commercial shore sta- 
tions as do interfere with the reception of signals by the naval and 
military stations concerned shall not use their transmitters during the 
first fifteen minutes of each hour, local standard time. The Secretary 
of Commerce may, on the recommendation of the department con- 
cerned, designate the station or stations which may be required to 
observe this division of time. 



RADIO ACT OF 1912 263 

GOVERNMENT STATIONS TO OBSERVE DIVISION OF TIME 

Thirteenth. The naval or military stations for which the above- 
mentioned division of time may be established shall transmit signals 
or radiograms only during the first fifteen minutes of each hour, local 
standard time, except in case of signals or radiograms relating to 
vessels in distress, as hereinbefore provided. 

USE OF UNNECESSARY POWER 

Fourteenth. In all circumstances, except in case of signals or 
radiograms relating to vessels in distress, all stations shall use the 
minimum amount of energy necessary to carry out any communi- 
cation desired. 

GENERAL RESTRICTIONS ON PRIVATE STATIONS 

Fifteenth. No private or commercial station not engaged in the 
transaction of bona fide commercial business by radio communication 
or in experimentation in connection with the development and manu- 
facture of radio apparatus for commercial purposes shall use a trans- 
mitting wave-length exceeding two hundred meters, or a transformer 
input exceeding one kilowatt, except by special authority of the 
Secretary of Commerce contained in the license of the station: 
Provided, That the owner or operator of a station of the character 
mentioned in this regulation shall not be liable for a violation of the 
requirements of the third or fourth regulations to the penalties of one 
hundred dollars or twenty-five dollars, respectively, provided in this 
section unless the person maintaining or operating such station shall 
have been notified in writing that the said transmitter has been found, 
upon tests conducted by the Government, to be so adjusted as to 
violate the said third and fourth regulations, and opportunity has been 
given to said owner or operator to adjust said transmitter in con- 
formity with said regulations. 

SPECIAL RESTRICTIONS IN" VICINITIES OF GOVERNMENT STATIONS 

Sixteenth. No station of the character mentioned in regulation 
fifteenth situated within five nautical miles of a naval or military 
station shall use a transmitting wave-length exceeding two hundred 
meters or a transformer input exceeding one-half kilowatt. 

SHIP STATIONS TO COMMUNICATE WITH NEAREST SHORE STATIONS 

Seventeenth. In general, the shipboard stations shall transmit their 
radiograms to the nearest shore station. A sender on board a vessel 
shall, however, have the right to designate the shore station through 
which he desires to have his radiograms transmitted. If this can not 



264 RADIO FOR ALL 

be done, the wishes of the sender are to be complied with only if the 
transmission can be effected without interfering with the service of 
other stations. 

LIMITATIONS FOR FUTURE INSTALLATIONS IN VICINITIES 
OF GOVERNMENT STATIONS 

Eighteenth. No station on shore not in actual operation at the 
date of the passage of this Act shall be licensed for the transaction 
of commercial business by radio communication within fifteen nauti- 
cal miles of the following naval or military stations, to wit: 
Arlington, Virginia; Key West, Florida; San Juan, Porto Rico; North 
Head and Tatoosh Island, Washington; San Diego, California; and 
those established or which may be established in Alaska and in the 
Canal Zone; and the head of the department having control of such 
Government stations shall, so far as is consistent with the transaction 
of governmental business, arrange for the transmission and receipt 
of commercial radiograms under the provisions of the Berlin con- 
vention of nineteen hundred and six and future international 
conventions or treaties to which the United States may be a party, at 
each of the stations above referred to, and shall fix the rates therefor, 
subject to control of such rates by Congress. At such stations and 
wherever and whenever shore stations open for general public business 
between the coast and vessels at sea under the provisions of the Berlin 
convention of nineteen hundred and six and future international con- 
ventions and treaties to which the United States may be a party shall 
not be so established as to insure a constant service day and night 
without interruption, and in all localities wherever or whenever such 
service shall not be maintained by a commercial shore station within 
one hundred nautical miles of a naval radio station, the Secretary of 
the Navy shall, so far as is consistent with the transaction of govern- 
mental business, open naval radio stations to the general public 
business described above, and shall fix rates for such service, subject 
to control of such rates by Congress. The receipts from such radio- 
grams shall be covered into the Treasury as miscellaneous receipts. 

SECRECY OF MESSAGES 

Nineteenth. No person or persons engaged in or having knowledge 
of the operation of any station or stations, shall divulge or publish 
the contents of any messages transmitted or received by such station, 
except to the person or persons to whom the same may be directed, or 
their authorized agent, or to another station employed to forward 
such message to its destination, unless legally required so to do by the 
court of competent jurisdiction or other competent authority. Any 



RADIO ACT OF 1912 265 

person guilty of divulging or publishing any message, except as herein 
provided, shall, on conviction thereof, be punished by a fine of not 
more than two hundred and fifty dollars or imprisonment for a period 
of not exceeding three months, or both fine and imprisonment, in the 
discretion of the court. 

PENALTIES 

For violation of any of these regulations, subject to which a license 
under sections one and two of this Act may be issued, the owner of 
the apparatus shall be liable to a penalty of one hundred dollars, 
which may be reduced or remitted by the Secretary of Commerce, and 
for repeated violations of any of such regulations, the license may 
be revoked. 

For violation of any of these regulations, except as provided in 
regulation nineteenth, subject to which a license under section three 
of this Act may be issued, the operator shall be subject to a penalty of 
twenty-five dollars, which may be reduced or remitted by the Secre- 
tary of Commerce, and for repeated violations of any such regulations, 
the license shall be suspended or revoked. 

SEC. 5. That every license granted under the provisions of this Act 
for the operation or use of apparatus for radio communication shall 
prescribe that the operator thereof shall not willfully or maliciously 
interfere with any other radio communication. Such interference 
shall be deemed a misdemeanor, and upon conviction thereof the 
owner or operator, or both, shall be punishable by a fine of not to 
exceed five hundred dollars or imprisonment for not to exceed one 
year, or both. 

SEC. 6. That the expression " radio communication " as used in 
this Act means any system of electrical communication by telegraphy 
or telephony without the aid of any wire connecting the points from 
and at which the radiograms, signals, or other communications are 
sent or received. 

SEC. 7. That a person, company, or corporation within the juris- 
diction of the United States shall not knowingly utter or transmit, or 
cause to be uttered or transmitted, any false or fraudulent distress 
signal or call or false or fraudulent signal, call, or other radiogram of 
any kind. The penalty for so uttering or transmitting a false or 
fraudulent distress signal or call shall be a fine of not more than two 
thousand five hundred dollars or imprisonment for not more than 
five years, or both, in the discretion of the court, for each and every 
such offense, and the penalty for so uttering or transmitting, or 
causing to be uttered or transmitted, any other false or fraudulent 
signal, call, or other radiogram shall be a fine of not more than one 



266 



RADIO FOR ALL 



thousand dollars or imprisonment for not more than two years, or 
both, in the discretion of the court, for each and every such offense. 

SEC. 8. That a person, company, or corporation shall not use or 
operate any apparatus for radio communication on a foreign ship in 
territorial waters of the United States otherwise than in accordance 
with the provisions of sections four and seven of this Act and so much 
of section five as imposes a penalty for interference. Save as afore- 
said, nothing in this Act shall apply to apparatus for radio communi- 
cation on any foreign ship. 

SEC. 9. That the trial of any offense under this Act shall be in the 
district in which it is committed, or if the offense is committed upon 
the high seas or out of the jurisdiction of any particular State or 
district the trial shall be in the district where the offender may be 
found or into which he shall be first brought. 

SEC. 10. That this Act shall not apply to the Philippine Islands. 

SEC. 11. That this Act shall take effect and be in force on and 
after four months from its passage. 

Approved, August 13, 1912. 

U. S. BROADCASTING STATIONS 
(Corrected to September 1, 1922) 

Call 

Letters Name City State 

KDKA Westinghouse El. & Mfg. 

Co. East Pittsburgh Pa. 

KDN Leo J. Meyberg Co. San Francisco Calif. 



Ware- 
Length 



360 



360-485 



KDPM Westinghouse Elec. & 

Mfg. Co. Cleveland Ohio 

KDPT Southern Electrical Co. San Diego Calif. 

KDYL Telegram Publishing Co. Salt Lake City Utah 

KDYM Savoy Theatre San Diego Calif. 
KDYN Great Western Radio 

Corp. Redwood City Calif. 

KDYO Carlson & Simpson San Diego Cal. 

KDYQ Ore. Inst. of Technology Portland Ore. 
KDYR Pasadena Star-News 

Pub. Co Pasadena Calif. 

KDYS The Tribune Great Falls Mont. 

KDYU Herald Publishing Co. Klamath Falls Ore. 

KDYV Cope & Cornwell Co. Salt Lake City Utah 

KDYW Smith, Hughes & Co. Phoenix Ariz. 

KDYX Star Bulletin Honolulu Hawaii 

JLDYT Rocky Mt. Radio Corp. Denver Colo, 



360 
360 



485 



RADIO ACT OF 1912 



267 



Call 
Letter! Name 

KDZA Arizona Daily Star 

KDZB Frank E. Sicfcrt 

KDZD W. R. Mitchell 

KDZE The Rhodes Co. 

KDZF Auto Club of Southern 
Calif. 

KDZG Cyrus Pierce & Co. 

KDZH Fresno Evening Herald 

KDZI Electric Supply Co. 

KDZJ Excelsior Radio Co. 

KDZK Nevada Mach. & Elec- 
tric Co. 

KDZL Rocky Mt. Radio Corp. . 

KDZM Hollingworth, E. H. 

KDZN Western Radio Corp. 

KDZP Newbery Electric Corp. 

KDZQ Motor Generator 

KDZR Bellingham Publishing 
Co. 

KDZT Seattle Radio Assoc. 
KDZW Claude W. Gerdes 

KDZX Glad Tidings Tabernacle 

KDZZ Kinney Bros. & Sipprell 

KFAB Pacific Radiophone Co. 

KFAC Glendale Daily Press 

KFAD McArthur Bros. Mercan- 
tile Co. 

KFAE State College of Wash- 
ington 

KFAF Western Radio Corp. 

KFAJ University of Colorado 

KFAN The Electric Shop 

KFAP Standard Publishing Co. 

KFAQ City of San Jose 

KFAR Studio Lighting Service 
Co. 

KFAS Reno Motor Supply Co. 

KFAT S. T. Donohue 

KFAU High School 

KFAV Cooke & Chapman 





Wave- 


City 


State Length 


Tucson 


Ariz. 360 


Bakersfield 


Calif. 360 


Los Angeles 


Calif. 360 


Seattle 


Wash. 360 


Los Angeles 


Calif. 360 


San Francisco 


Calif. 360 


Fresno 


Calif. 360 


Wenatchee 


Wash. 360 


Eugene 


Ore. 360 


Reno 


Nev. 360 


Ogden 


Utah 360 


Centralia 


Wash. 360 


Denver 


Colo. 360 


Los Angeles 


Calif. 360 


Denver 


Colo. 360 


Bellingham 


Wash. 360 


Seattle 


Wash. 360 


San Francisco 


Calif. 360 


San Francisco 


Calif. 360 


Everett 


Wash. 360 


Portland 


Ore. 360 


Glendale 


Calif. 360 


Phoenix 


Ariz. 360 


Pullman 


Wash. 360 


Denver 


Colo. 360 


Boulder 


Colo. 360 


Moscow 


Idaho 360 


Butte 


Mont. 360 


San Jos6 


Calif. 360 


Hollywood 


Calif. 360 


Reno 


Nevada 360 


Eugene 


Ore. 360 


Boise 


Idaho 




360-485 


Venice 


Calif. 360 



268 



RADIO FOR ALL 



Call 
Lettiri Name 

KFAW Register Radio Den 

Radiophone 

KFAY W. J. Virgin Milling Co. 
KFBA Ramey & Bryant Radio 

Co. 

KFBB F. A. Buttrey & Co. 
KFBC Normal Heights Sta., W. 

K. Azbill 

KFBD Clarence V. Welch 
KFBE R. H. Horn, Cline's 

Electric Shop 

KFBF Butte School of Teleg- 
raphy 
KFBG First Presbyterian 

Church 

KFBH Thomas Musical Co. 
KFBJ Idaho Radio Supply Co. 
KFBK Kimball-Upson Co. 
KFBL Leese Bros. 
KFBM Cook & Foster 
KFBN Borch Radio Corp. 
KFC Northern Radio & Elec. 

Co. 

KFDB John D. McKee 
KFI Carl C. Anthony 
KFU The Precision Shop 
KFV Foster Bradbury Radio 

Store 

KFZ Doerr-Mitchell Elec. Co. 
KGB Wm. H. Mullins Elec. Co. 
KGC Elec. Lighting & Elec. Co. 
KGF Pomona Fixture & Wir- 
ing Co. 
KGG Hallock & Watson Radio 

Serv. 
KGN Northwest Radio Mfg. 

Co. 

KGO Altadena Radio Labor- 
atory 

KGU Marion H. Mulrony 
KGW Oregonian Publishing Co. 



City 


Wart- 
State Length 


Santa Ana 


Calif. 


360 


Central Point 


Ore. 


360 


Lewiston 


Idaho 


360 


Havre 


Mont. 


360 


San Diego 


Calif. 


360 


Hanford 


Calif. 


360 


San Luis Obispo 


Calif. 


360 


Butte 


Mont. 


860 


Tacoma 


Wash. 


360 


Marshfleld 


Ore. 


360 


Boise 


Idaho 


360 


Sacramento 


Calif. 


360 


Everett 


Wash. 


360 


Astoria 


Ore. 


360 


(portable) 


Calif. 


360 


Seattle 


Wash. 


360 


San Francisco 


Calif. 


360 


Los Angeles 


Calif. 


360 


Gridley 


Calif. 


360 


Yakima 


Wash. 


360 


Spokane 


Wash. 


360 


Tacoma 


Waik 


360 


Hollywood 


Calif. 


360 


Pomona 


Calif. 


360 


Portland 


Ore. 


860 


Portland 


Ore. 


360 


Altadena 


Calif. 


860 


Honolulu 


Hawaii 


360 


Portland 


Ore. 


860 



RADIO ACT OF 1912 


269 


Call 


Wave- 


Letters Name City 


State Length 


KGY St. Martin's College 




(Rev. S. Ruth) Lacey 


Wash. 360 


KHD C. F. Aldrich Marble 




and Granite Co. Colorado -Springs 


Colo. 485 


KHJ C. R. Kierulff & Co. Los Angeles 


Calif. 360 


KHQ Louis Wasmer Seattle 


Wash. 360 


KJC Standard Radio Co. Los Angeles 


Calif. 360 


KJJ The Radio Shop Sunnyvale 


Calif. 360 


KJQ C. O. Gould Stockton 


Calif. 360 


KJR Vincent I. Kraft Seattle 


Wash. 




360-485 


KJS Bible Inst. of Los Angeles Los Angeles 


Calif. 360 


KLB J. J. Dunn & Co. Pasadena 


Calif. 360 


KLN Hotel Del Monte Del Monte 


Calif. 360 


KLP Colin B. Kennedy Los Altos 


Calif. 360 


KLS Warner Brothers Oakland 


Calif. 360 


KLX Tribune Publishing Co. Oakland 


Calif. 360 


KLZ Reynolds Radio Co. Denver 


Colo. 360 


KMC Lindsay Weatherill & Co. Riedley 


Calif. 360 


KMJ San Joaquin Lt. & Power 




Co. Fresno 


Calif. 860 


KMO Love Electric Co. Tacoma 


Wash. 360 


KNI T. W. Smith Eureka 


Calif. 360 


KNJ Roswell Public Service 




Co. Roswell 


N.M. 360-485 


KNN Bullock's Los Angeles 


Calif. 360 


KNR Beacon Light Co. Los Angeles 


Calif. 360 


KNT North Coast Products Co. Aberdeen 


Wash. 360 


KNV Radio Supply Co. Los Angeles 


Calif. 360 


KNX Electric Ltg. Supply Co. Los Angeles 


Calif. 360 


KOA Y.M.C.A. Denver 


Colo. 485 


KOB N.M. College Agr. & Mch. 




Arts State College 


N.M. 360-485 


KOE Spokane Chronicle Spokane 


Wash. 360 


KOG Western Radio Electric 




Co. Los Angeles 


Calif. 360 


KOJ University of Nevada Reno 


Nev. 360 


KON Holzwasser, Inc. San Diego 


Calif. 860 


KOP Detroit Police Dep't Detroit 


Mich. 360 


KOQ Modesto Evening News Modesto 


Calif. 360 


KPO Hale Brothers San Francisco 


Calif. 360 


KQI Univ. of California Berkeley 


Calif. 360 



270 



RADIO FOR ALL 



CaD 




Wave- 


Letters Name 


City 


State Length 


KQL Arno H. Kluge 


Los Angeles 


Calif. 360 


KQP Blue Diamond Electric 






Co. 


Hood River 


Ore. 360-485 


KQT Elec. Power & Appliance 






Co. 


Yakima 


Wash. 360 


KQV Doubleday-Hill Elec. Co. 


Pittsburgh 


Pa. 860 


KQW Charles D. Herrold 


San Jose 


Calif. 360 


KQY Stubbs Electric Co. 


Portland 


Ore. 360 


KRE Maxwell Electric Co. 


Berkeley 


Calif. 360 


KSC O. A. Hale & Co. 


San Jose 


Calif. 360 


KSD Post Dispatch 


St. Louis 


Mo. 360 


KSL The Emporium 


San Francisco 


Calif. 360 


KSS Prest & Dean Radio Co. 


Long Beach 


Calif. 360 


KTW First Presbyterian 






Church 


Seattle 


Wash. 360 


KUO Examiner Printing Co. 


San Francisco 


Calif. 






360-485 


KUS City Dye Works & Laun- 






dry Co. 


Los Angeles 


Calif. 860 


KUY Coast Radio Co. 


El Monte 


Calif. 860 


KVQ J. C. Hobrecht 


Sacramento 


Calif. 360 


KWG Portable Wireless Tele. 






Co. 


Stockton 


Calif. 860 


KWH Los Angeles Examiner 


Los Angeles 


Calif. 360 


KXD Herald Publishing Co. 


Modesto 


Calif. 360 


KXS Braun Corp. 


Los Angeles 


Calif. 360 


KYF Thearle Music Co. 


San Diego 


Calif. 860 


KYG Willard P. Hawley, Jr. 


Portland 


Ore. 360 


KYI Alfred Harrell 


Bakersfield 


Calif. 360 


KYJ Leo J. Meyberg Co. 


Los Angeles 


Calif. 






360-485 


KYW Westinghouse Elec. & 






Mfg. Co. 


Chicago 


111. 360-485 


KYY Radio Telephone Shop 


San Francisco 


Calif. 360 


KZC Pub. Mkt. & Mkt. Stores 






Co. 


Seattle 


Wash. 360 


KZI Irving S. Cooper 


Los Angeles 


Calif. 360 


KZM Preston D. Allen 


Oakland 


Calif.360-485 


KZN The Deseret News 


Salt Lake City 


Utah 360-485 


KZV Wenatchee Battery & 






Motor Co. 


Wenatchee 


Wash. 360 



RADIO ACT OF 1912 



Call 






Wave- 


ijflu 
Letters 


Name 


City 


State Length 


KZY 


Atl. & Pac. Radio Supply 








Co. 


Oakland 


Calif. 360 


WAAB 


Times Picayune 


New Orleans 


La. 360 


WAAC 


Tulane University 


New Orleans 


La. 360 


WAAD 


Ohio Mechanics Institute 


Cincinnati 


Ohio 360 


WAAE 


St. Louts Chamber of 








Commerce 


St. Louis 


Mo. 360 


WAAF 


Union Stock Yds. & 








Transit Co. 


Chicago 


111. 860-485 


WAAG 


Elliott Electric Co. 


Shreveport 


La. 360 


WAAH 


Commonwealth Electric 








Co. 


St. Paul 


Minn. 360 


WAAJ 


Eastern Radio Institute 


Boston 


Mass. 360 


WAAK 


Gimbel Brothers 


Milwaukee 


Wis. 360 


WAAL 


Minn. Tribune & A. 








Beamish Co. 


Minneapolis 


Minn. 360 


WAAM 


I. R. Nelson Co. 


Newark 


N.J. 360 


WAAN 


University of Missouri 


Columbia 


Mo. 360 


WAAO 


Radio Service Co. 


Charlestown 


W. Va. 360 


WAAP 


Otto W. Taylor 


Wichita 


Kans. 360 


WAAQ 


New England Motor 








Sales Co. 


Greenwich 


Conn. 360 


WAAR 


Groves Thornton Hdwe. 








Co. 


Huntington 


W. Va. 360 


WAAS 


Georgia Radio Co. 


Decatur 


Ga. 360 


WAAV 


Athens Radio Co. 


Athens 


Ohio 360 


WAAW 


Omaha Grain Exchange 


Omaha 


Neb. 360 


WAAX 


Radio Service Corp. 


Crafton 


Pa. 360 


WAAY 


Yahrling Rayner Music 








Co. 


Youngstown 


Ohio 360 


WAAZ 


Hollister-Miller Motor 








Co. 


Emporia 


Kans. 360 


WAH 


Midland Refining Co. 


El Dorado 


Kans.360-485 


WBAA 


Purdue University 


West Lafayette 


Ind. 360 


WBAB 


Andrew J. Potter 


Syracuse 


N.Y. 860 


WBAD 


Sterling Electric Co. 


Minneapolis 


Minn. 360 


WBAE 


Bradley Polytechnic Inst. 


Peoria 


111. 360-485 


WBAF 


Fred M. Middleton 


Moorestown 


N.J. 360 


WBAG 


Diamond State Fibre Co. 


Bridgeport 


Pa. 360-485 


WBAH 


The Dayton Co. 


Minneapolis 


Minn. 360 


WBAJ 


Marshall-Gerken Co. 


Toledo 


Ohio 360 



272 



RADIO FOR ALL 



Call 

Letters Name 

WBAM I. B. Rennyson 
WBAN Wireless Phone Corp. 
WBAO James Millikin Univer- 
sity 

WBAP Wortham-Carter Pub. Co. 
WBAQ Myron L. Harmon 
WBAU Republican Publishing 

Co. 

WBAV Erner & Hopkins 
WBAW Marietta College 
WBAX John H. Stenger, Jr. 
WBAY American Tel. & Tel. Co 
WBAZ Times Dispatch Pub. Co. 
WBL T. & H. Radio Co. 
WBS D. W. May, Inc. 
WBT Southern Radio Corp. 
WBU City of Chicago 
WBZ Westinghouse Elec. & 

Mfg. Co. 
WCAB Newberg News Ptg. & 

Pub. Co. 

WCAC John Fink Jewelry Co. 
WCAD St. Lawrence University 
WCAE Kaufman & Baer Co. 
WCAG Daily States Pub. Co. 
WCAH Entrekin Electric Co. 
WCAJ Nebraska Wesleyan Univ. 
WCAK Alfred P. Daniel 
WCAL St. Olaf College 
WCAM Villanova College 
WCAN Southeastern Radio Tel. 

Co. 

WCAO Sanders & Stayman Co. 
WCAP Central Radio Service 
WCAQ Tri-State Radio Mfg. & 

Sup. Co. 

WCAR Alamo Radio Electric Co. 
WCAS Wm. H. Dunwoody ]n- 

dust. Inst. 
WCAT So. Dakota School of 

Music 





Wave- 


City 


State Length 


New Orleans 


La. 860 


Paterson 


N.J. 360 


Decatur 


111. 360 


Fort Worth 


Tex. 360-485 


South Bend 


Ind. 360 


Hamilton 


Ohio 360 


Columbus 


Ohio 360 


Marietta 


Ohio 360 


Wilkes-Barre 


Pa, 360 


New York 


N.Y. 360 


Richmond 


Va. 360 


Anthony 


Kans. 360 


Newark 


N.J. 360 


Charlotte 


N.C. 360-485 


Chicago 


111. 360 


Springfield 


Mass. 360 


Newberg 


N. Y. 360 


Fort Smith 


Ark. 360 


Canton 


Ohio 360 


Pittsburgh 


Pa. 360 


New Orleans 


La. 360 


Columbus 


Ohio 360 


University Place 


Neb. 360-485 


Houston 


Texas 360 


Northfield 


Minn. 860 


Villanova 


Pa. 360 


Jacksonville 


Fla. 360 


Baltimore 


Md. 360 


Decatur 


111. 360 


Defiance 


Ohio 360 


San Antonio 


Texas 360 


Minneapolis 


Minn. 360 


Rapid City 


S. Dak. 485 



RADIO ACT OF 1912 



273 



Call 
Letters 

WCAU 

WCAV 
WCAW 

WCAX 
WCAY 
WCAZ 

WCE 

WCJ 

WCK 

WCM 

WCN 

WCX 

WDAA 

WDAB 

WDAC 

WDAD 

WDAE 

WDAF 

WDAG 

WDAH 

WDAI 
WDAJ 

WDAK 
WDAL 
WDAN 
WDAO 
WDAP 

WDAQ 

WDAR 
WDAS 
WDAT 
WDAU 
WDAV 

18 



Philadelphia Radiophone 

Co. 

J. C. Dice Electric Co. 
Q. Herald & Quincy 

Elec. Sup. Co. 
University of Vermont 
Kesselman O'Driscoll Co. 
R. E. Compton & Q. Whig 

General 

Findley Electric Co. 
A. C. Gilbert 
Stix-Baer-Fuller 
University of Texas 
Clark University 
Detroit Free Press 
Ward Belmont School 
H. C. Summers & Son 
Illinois Watch Co. 
Wm. L. Harrison 
Tampa Daily Times 
Kansas City Star 
J. Lawrence Martin 
Mine & Smelter Supply 

Co. 

Hughes Electrical Corp. 
Atlanta & West Point 

R. R. Co. 
The Courant 
Florida Times Union 
Glenwood Radio Corp. 
Automotive Electric Co. 
Mid-West Radio Central, 

Inc. 
Hartman Riker Elec. & 

Mch. Co. 
Lit Bros. 
Samuel A. Waite 
Delta Electric Co. 
Slocum & Kilburn 
Muskogee Daily Phoenix 





Wave- 


City 


State Length 


Philadelphia 


Pa. 360 


Little Rock 


Ark. 360 


Quincy 


111. 360 


Burlington 


Vt. 860 


Milwaukee 


Wis. 360 


Quincy 


111. 360 


Minneapolis 


Minn. 360 


New Haven 


Conn. 360 


St. Louis 


Mo. 860 


Austin 


Tex. 360-485 


Worcester 


Mass.360-485 


Detroit 


Mich.360-485 


Nashville 


Tenn. 360 


Portsmouth 


Ohio 360 


Springfield 


III. 485 


Lindsborg 


Kans. 360 


Tampa 


Fla. 360-485 


Kansas City 


Mo. 360 


Amarillo 


Texas 360 


El Paso 


Texas 360 


Syracuse 


N. Y. 360 


College Park 


Ga. 360 


Hartford 


Conn. 360 


Jacksonville 


Fla. 360-485 


Shreveport 


La. 360 


Dallas 


Texas 360 


Chicago 


111. 360 


Brownsville 


Pa. 360 


Philadelphia 


Pa. 360 


Worcester 


Mass. 360 


Worcester 


Mass. 360 


New Bedford 


Mass. 360 


Muskogee 


Okla. 860 



274 RADIO FOR ALL 


Call 
Letters Name 


City 


Wave- 
State Length 


WDAW Georgia Rwy. & Power 






Co. 


Atlanta 


Ga. 360-485 


WDAX First National Bank 


Centerville 


Iowa 360 


WDAY Kenneth M. Hance 


Fargo 


N. Dak. 






360-485 


WDM Church of the Covenant 


Washington 


D. C. 


WDT Ship Owners' Radio Ser- 






vice 


New York 


N.Y. 360 


WDV Yeiser, John O., Jr. 


Omaha 


Neb. 360 


WDY Radio Corp. of America 


Roselle Park 


N.J. 360 


WDZ James L. Bush 


Tuscola 


111. 360 


WEAA Fallian & Lathrop 


Flint 


Mich. 360 


WEAB Standard Radio Equip. 






Co. 


Fort Dodge 


Iowa 360 


WEAC Baines Elec. Serv. Co. 


Terre Haute 


Ind. 360 


WEAD N. W. Kansas Radio 






Supply Co. 


Atwood 


Kan. 360 


WEAE Virginia Polytechnic Inst. 


Blacksburg 


Va. 360 


WEAF Western Electric Co. 


New York 


N.Y. 360 


WEAG Nichols-Hineline-Bassett 






Lab. 


Edgewood 


R.I. 360 


WEAH W. Bd. of Trd. & Lander 






Radio Co. 


Wichita 


Kan. 360-485 


WEAI Cornell University 


Ithaca 


N.Y. 360 


WEAJ Univ. of So. Dakota 


Vermilion 


S. Dak. 360 


WEAK Julius B. Abercrombie 


St. Joseph 


Mo. 360 


WEAM Boro of North Plainfield 


No. Plainfield 


N.J. 360 


WEAN Shepard Co. 


Providence 


R.I. 360 


WEAO Ohio State University 


Columbus 


Ohio 360-485 


WEAP Mobile Radio Co. 


Mobile 


Ala. 360 


WEAQ Y.M.C.A. 


Berlin 


N.H. 360 


WEAR Baltimore Amer. & News 






Pub. Co. 


Baltimore 


Md. 360 


WEAS Hecht Co. 


Washington 


D.C. 360 


WEAT John J. Fogarty 


Tampa 


Fla. 360 


WEAU Davidson Bros. Co. 


Sioux City 


Iowa 360 


WEAV Sheridan El. Serv. Co. 


Rushville 


Neb. 360 


WEAW Arrow Radio Labora- 






tories 


Anderson 


Ind. 360 


WEAX T. J. M. Daly 


Little Rock 


Ark. 360-485 


WEAY Will Horwitz, Jr. 


Houston 


Texas 360 



RADIO ACT OF 1912 



275 



Call 
Letters Name 

WEAZ Donald Redmond 
WEB BenwoodCo. 
WEH Midland Refining Co. 
WEV Hurlburt-Still Electrical 

Co. 

WEW St. Louis University 
WEY Cosradio Co. 
WFAA A. H. Belo & Co. 
WFAB Carl F. Woese 
WFAC Superior Radio Co. 
WFAD Watson Weldon Motor 

Sup. Co. 

WFAF H. C. Spratley Co. 
WFAG Radio Engineering Lab- 
oratory 

WFAH Electric Supply Co. 
WFAJ Hi Grade Wireless Instr. 

Co. 

WFAK Domestic Electric Co. 
WFAL Houston Chronicle Pub. 

Co. 

WFAM Times Pub. Co. 
WFAN Hutchinson Elec. Serv. 

Co. 

WFAP Brown's Business College 
WFAQ Mo. Wesleyan College & 

Cameron Radio Co. 
WFAR Hall & Stubs 
WFAS United Radio Corp. 
WFAT Daily Argus Leader 
WFAU Edwin C. Lewis 
WFAV University of Nebraska 
WFAW Miami Daily Metropolis 
WFAX Arthur L. Kent 
WFAY Daniels Radio Supply Co. 
WFAZ South Carolina Radio 

Shop 

WFI Strawbridge & Clothier 
WFO Rike-Kumler Co. 
WGAB Q.R.V. Radio Co. 



City 


Wave- 
State Length 


Waterloo 


Iowa 360 


St. Louis 


Mo. 360 


Tulsa 


Okla. 360-485 


Houston 


Tex. 360-485 


St. Louis 


Mo. 360-485 


Wichita 


Kan. 360-485 


Dallas 


Tex. 360-485 


Syracuse 


N.Y. 360 


Superior 


Wis. 360 


Salina 


Kan. 360 


Poughkeepsie 


N.Y. 360 


Waterford 


N.Y. 360 


Port Arthur 


Texas 860 


Asheville 


N.C. 360 


Brentwood 


Mo. 360 


Houston 


Tex. 360-485 


St. Cloud 


Minn. 360 


Hutchinson 


Minn.360-485 


Peoria 


111. 860 


Cameron 


Mo. 360 


Stamford 


Me. 360 


Ft. Wayne 


Ind. 360 


Sioux Falls 


S. Dak. 360 


Boston 


Mass. 360 


Lincoln 


Nebr. 360-485 


Miami 


Fla. 360 


Binghamton 


N.Y. 360 


Independence 


Kan. 360 


Charleston 


S.C. 360 


Philadelphia 


Pa. 360-485 


Dayton 


Ohio 360-485 


Houston 


Texas 360 



276 RADIO FOR ALL 




Call 
Letters Name City 


State Length 


WGAC Orpheum Radio Stores 




Co. Brooklyn 


N.Y. 360 


WGAD Spanish American School 




of Radio- Telegraphy Ensenada 


P.R. 360 


WGAF Goller Radio Service Tulsa 


Okla. 360 


WGAH New Haven Electric Co. New Haven 


Conn. 360 


WGAJ W. H. Goss Shenandoah 


Iowa 360 


WGAK Macon Electric Co. Macon 


Ga. 360 


WGAL Lancaster Elec. Supply 




& Const. Co. Lancaster 


Pa. 360 


WGAM Orangeburg Radio 




Equipment Co. Orangeburg 


S.C. 360 


WGAN Cecil E. Lloyd Pensacola 


Fla. 360 


WGAQ Glenwood Radio Corp. Shreveport 


La. 360 


WGAR Southwest American Fort Smith 


Ark. 360 


WGAS The Ray-Di-Co Organ- 




ization Chicago 


111. 360 


WGAT American Legion, Dept. 




of Nebraska Lincoln 


Neb. 360 


WGAU Marcus G. Limb Wooster 


Ohio 360 


WGAW Ernest C. Albright Altoona 


Pa. 360 


WGAY North Western Radio Co. Madison 


Wis. 360 


WGAZ The South Bend Tribune South Bend 


Ind. 360 


WGF The Register & Tribune Des Moines 


Iowa 360-485 


WGH Montgomery Light & 




Power Co. Montgomery 


Ala. 360-485 


WGI Amer. Radio Research 




Corp. Medford Hillside 


Mass. 360 


WGL Thomas F. J. Hewlett Philadelphia 


Pa. 360 


WGR Federal Tel. & Tel. Co. Buffalo 


N.Y. 360-485 


WGU The Fair Chicago 


111. 360 


WGV Interstate Electric Co. New Orleans 


La. 360 


WGY General Electric Co. Schenectady 


N.Y. 360 


WHA University of Wisconsin Madison 


Wis. 360-485 


WHAA State University of Iowa Iowa City 


Iowa 360 


WHAB Clark W. Thompson Galveston 


Texas 




360-485 


WHAC Cole Bros. Electric Co. Waterloo 


Iowa 360 


WHAD Marquette University Milwaukee 


Wis. 360 



WHAE Automotive Electric Ser- 
vice Co. Sioux City 



Iowa 



RADIO ACT OF 1912 



277 



Call 
Letters 

WHAF 
WHAG 
WHAH 
WHAT 

WHAJ 
WHAK 
WHAL 
WHAM 
WHAN 
WHAO 
WHAP 
WHAQ 
WHAR 

WHAS 
WHAT 
WHAU 
WHAV 

WHAW 
WHAX 
WHAY 
WHAZ 

WHB 
WHO 
WHK 
WHN 

WHQ 
WHU 
WHW 
WIAA 

WIAB 
WIAC 
WIAD 



Name 

Radio Electric Co. 
University of Cincinnati 
John T. Griffin 
Radio Equipment & Mfg. 

Co. 

Bluefleld Daily Telegraph 
Roberts Hdwe. Co. 
Phillips Jeffery & Derby 
University of Rochester 
Southwestern Radio Co. 
Frederic A. Hill 
Dewey L. Otta 
Semmes Motor Co. 
Paramount Radio & Elec. 

Co. 
Courier-Journal and 

Louisville Times 
Yale Democrat - Yale 

Telephone Co. 
Corinth Radio Supply 

Co. 
Wilmington Elec. 

Specialty Co., Inc. 
Pierce Electric Co. 
Holyoke Street Ry. Co. 
The Huntington Press 
Rensselaer Polytechnic 

Inst. 

Sweeney School Co. 
West Virginia University 
Warren R. Cox 
Ridgewood Times Ptg. & 

Pub. Co. 

Rochester Times Union 
Wm. B. Duck Co. 
Stuart W. Seeley 
Waupoca Civic & Com- 
merce Assoc. 
Joslyn Automobile Co. 
Galveston Tribune 
Ocean City Yacht Club 





Wave- 


City 


State Length 


Pittsburgh 


Pa. 360 


Cincinnati 


Ohio 360 


Joplin 


Mo. 360 


Davenport 


Iowa 360 


Bluefield 


W. Va. 360 


Clarksburg 


W. Va. 360 


Lansing 


Mich. 360 


Rochester 


N.Y. 360 


Wichita 


Kansas 360 


Savannah 


Ga. 360 


Decatur 


111. 360 


Washington 


D.C. 360 


Atlantic City 


N.J. 360 


Louisville 


Ky. 360-485 


Yale 


Okla. 360 


Corinth 


Miss. 360 


Wilmington 


Del. 360 


Tampa 


Fla. 360 


Holyoke 


Mass. 360 


Huntington 


Ind. 360-485 


Troy 


N.Y. 360 


Kansas City 


Mo. 860-485 


Morgantown 


W. Va. 860 


Cleveland 


Ohio 360 


Ridgewood 


N.Y. 360 


Rochester 


N.Y. 360-485 


Toledo 


Ohio 360 


East Lansing 


Mich. 485 


Waupaca 


Wls. 360 


Rockford 


111. 360 


Galveston 


Tex. 360 


Ocean City 


N.J. 360 



278 


RADIO FOR ALL 


Call 








Wave- 


Letters 


Name 


City 


State 


Length 


WIAE 


Mrs. Robert E. Zimmer- 










man 


Vincon 


Iowa 


360 


WIAF 


Gustav A. De Cortin 


New Orleans 


La. 


360 


WIAG 


Matthews Elec. Supply Co. 


Birmingham 


Ala. 


360 


WIAH 


Continental Radio & 










Mfg. Co. 


Newton 


Iowa 


360 


WIAI 


Heer Stores Co. 


Springfield 


Mo. 


360 


WIAJ 


Fox River Valley Radio 










Co. 


Nunah 


Wis. 


360 


WIAK 


Daily Journal-Stockman 


Omaha 


Neb. 


360-485 


WIAL 


Standard Service Co. 


Norwood 


Ohio 


360 


WIAN 


Chronicle & News 


Allentown 


Pa. 


360 


WIAO 


School of Eng. of Mil- 










waukee and Wisconsin 










News 


Milwaukee 


Wis. 


360 


WI\P 


Radio Development 










Corp. 


Springfield 


Mass 


360 


WIAQ 


Chronicle Publishing Co. 


Marion 


Ind. 


360 


WIAR 


J. A. Rudy & Sons 


Paducah 


Ky. 


360 


WIAS 


Burlington Hawkeye & 










Home Electric Co. 


Burlington 


Iowa 


360 


WIAT 


Leon T. Noel 


Tarkio 


Mo. 


360 


WIAU 


American Trust & Sav- 










ings Bank 


Le Mars 


Iowa 


360 


WIAV 


New York Radio Labor- 










atories 


Binghamton 


N.Y. 


360 


WIAW 


Saginaw Radio & Elec- 










tric Co. 


Saginaw 


Mich. 


360 


WIAX 


Capital Radio Co. (Paul 










C. Rohwer) 


Lincoln 


Neb. 


360 


WIAY 


Woodward & Lothrop 


Washington 


D.C. 


360 


WIAZ 


Electric Supply Sales Co. 


Miami 


Fla. 


860 


WIK 


K. & L. Electric Co. 


McKeesport 


Pa. 


360 


WIL 


Continental Elec. Sup. Co. 


Washington 


D.C. 


360 


WIP 


Gimbel Brothers 


Philadelphia 


Pa. 


360 


WIZ 


Cincinnati Radio Mfg. 










Co. 


Cincinnati 


Ohio 


360-485 


WJAB 


American Radio Co. 


Lincoln 


Neb. 


360 


WJAC 


Redell Co. 


Joplin 


Mo. 


360 


WJAD 


Jackson's Radio Engi- 










neering Laboratories 


Waco 


Texas 360 



RADIO ACT OF 191* 



Call 
Letters Name 

WJAE The Texas Radio Syndi- 
cate 

WJAF Muncie Press-Smith Elec- 
tric 

WJAG Norfolk Daily News 

WJAH Central Park Amuse- 
ment Co. 

WJAJ Y.M.C.A. 

WJAK White Radio Labora- 
tory 

WJAL Victor Radio Corp. 

WJAM D. M. Perham 

WJAN Peoria Star-Peoria Radio 
Sales Co. 

WJAP Kelley-Duluth Co. 

WJAQ Capper Publications 

WJAR The Outlet Co. 

(J. Samuels & Bro.) 

WJAS Pittsburgh Radio Supply 
Co. 

WJAT Kelley-Vawter Jewelry 
Co. 

WJAU Yankton College 

WJAX Union Trust Co. 

WJAZ Chicago Radio Labo- 
ratory 

WJD Richard H. Howe 
WJH White & Boyer Co. 
WJK Service Radio Equip. Co. 
WJT Electric Equipment Co. 
WJX DeForest Radio Tel. & 

Tel. Co. 

WJZ Westinghouse Elec. & 
Mfg. Co. 

WKAA H. F. Paap 

WKAC Star Publishing Co. 
WKAD Chas. Looff 
WKAF W. S. Radio Supply Co. 
WKAG Edwin T. Bruce, M.D. 
WKAH Planet Radio Co. 



City 
San Antonio 

Muncie 
Norfolk 

Rockford 
Dayton 



State 



270 

Wave- 
Length 



Texas 360 



Ind. 
Neb. 



111. 
Ohio 



360 
360 



360 
360 



Stockdale Ohio 360 

Portland Me. 360 

Cedar Rapids Iowa 360 



Peoria 
Duluth 
Topeka 

Providence 
Pittsburgh 

Marshall 
Yankton 
Cleveland 

Chicago 

Granville 

Washington 

Toledo 

Erie 

New York 

Newark 
Cedar Rapids 

Lincoln 

East Providence 

Wichita Falls 

Louisville 



111. 360 

Minn. 360 
Kansas 360 



360 



R. I. 
Pa. 

Mo. 

S. Dak. 
Ohio 

111. 

Ohio 

D.C. 

Ohio 

Pa. 

N.Y. 



N.J. 360 
Iowa 

200-360-485 

Neb. 360 

R. I. 360 

Texas 360 

Ky. 360 



360 



West Palm Beach Fla. 



280 RADIO FOR ALL 


Call 






Wave- 


Letters 


Name 


City 


State Length 


WKAJ 


Fargo Plumbing and 








Heating Co. 


Fargo 


N. Dak. 360 


WKAK 


Okfuskee County News 


Okemah 


Okla. 360 


WKAL 


Gray & Gray 


Orange 


Texas 360 


WKAM 


Hastings Daily Tribune 


Hastings 


Neb. 360 


WKAN 


Alabama Radio Mfg. Co. 


Montgomery 


Ala. 360 


WKAP 


Dutee W. Flint 


Cranston 


R. I. 360 


WKAQ 


Radio Corp. of Porto 








Rico 


San Juan 


P. R. 360 


WKAR 


Michigan Agricultural 








College 


East Lansing 


Mich. 360 


WKAS 


L. E. Lines Music Co. 


Springfield 


Mo. 360 


WKAT 


Frankfort Morning 








Times 


Frankfort 


Ind. 360-485 


WKAV 


Laconia Radio Club 


Laconia 


N. H. 360 


WKAW 


Turner Cycle Co. 


Beloit 


Wis. 360 


WKAX 


Wm. A. MacFarland 


Bridgeport 


Conn. 360 


WKAY 


Brenau College 


Gainesville 


Ga. 360 


WKAZ 


London's Music and 








Jewelry Co. 


Wilkes Barre 


Pa. 360 


WKC 


Joseph M. Zamoiski Co. 


Baltimore 


Md. 360 


WKN 


Riechman Crosby Co. 


Memphis 


Tenn.360-485 


WKY 


Oklahoma Radio Shop 


Oklahoma City 


Okla. 








360-485 


WLAB 


George F. Grossman 


Carrollton 


Mo. 360 


WLAC 


North Carolina State 








College 


Raleigh 


N. C. 360 


WLAD 


Arvanette Radio Supply 








Co. 


Hastings 


Neb. 360 


WLAF 


Johnson Radio Co. 


Lincoln 


Neb. 360 


WLAH 


Samuel Woodworth 


Syracuse 


N. Y. 360 


WLAJ 


Waco Electrical Supply 








Co. 


Waco 


Texas 360 


WLB 


University of Minnesota 


Minneapolis 


Minn.360-485 


WLK 


Hamilton Mfg. Co. 


Indianapolis 


Ind. 360-485 


WLW 


Crosley Mfg. Co. 


Cincinnati 


Ohio 360-485 


WMAD 


Atchinson County Mail 


Rock Port 


Mo. 360 


WMAH 


General Supply Co. 


Lincoln 


Neb. 360 


WMAM 


Beaumont Radio De- 








velopment Co. 


Beaumont 


Texas 360 


WMB 


Auburn Electrical Co. 


Auburn 


Me. 360 



RADIO ACT OF 1912 



281 



Call 
Letters Name 

WMC Columbia Radio Co. 
WMH Precision Equipment Co. 

WMU Doubleday-Hill Electric 

Co. 
WNAL R. J. Rockwell 

WNJ Shotton Radio Mfg. Co. 

WNO Wireless Tel. Co. of Hud- 
son County 

WOC Palmer School of Chiro- 
practic 

WOE Buckeye Radio Service 
Co. 

WOH Hatfield Electric Co. 
WOI Iowa State College 

WOK Pine Bluff Co. 

WOO John Wanamaker 

WOQ Western Radio Co. 

WOR L. Bamberger & Co. 

WOS Mo. State Marketing 
Bureau 

WOU Metropolitan Utilities 
District 

WOZ Palladium Printing Co. 

WPA Fort Worth Record 

WPE Central Radio Co. 

WPG Nushawg Poultry Farm 
WPI Electric Supply Co. 
WPJ St. Joseph's College 

WPL Fergus Electric Co. 

WPM Thomas J. Williams 

WPO United Equipment Co. 

WRK Doron Bros. Electric Co. 

WRL Union College 

WRM University of Illinois 

WRP Federal Inst. of Radiotel. 

WRR D. Police & Fire Signal 
Dept. 

WRW Tarrytown Radio Re- 
search Lab. 

WSB Atlanta Journal 
WSL J. & M. Electric Co. 





Wave- 


City 


State Length 


Youngstown 


Ohio 360 


Cincinnati 


Ohio 360-485 


Washington 


D.C. 360 


Omaha 


Neb. 360 


Albany 


N.Y. 360 


Jersey City 


N.J. 360 


Davenport 


Iowa 360-485 


Akron 


Ohio 360 


Indianapolis 


Ind. 360 


Hines 


Iowa 360-485 


Pine Bluff 


Ark. 360 


Philadelphia 


Pa, 860 


Kansas City 


Mo. 360-485 


Newark 


N.J. 360 


Jefferson City 


Mo. 485 


Omaha 


Neb. 360-485 


Richmond 


Ind. 360-485 


Ft. Worth 


Tex. 360-485 


Kansas City 


Mo. 860 


New Lebanon 


Ohio 860 


deal-field 


Pa. 360 


Philadelphia 


Pa. 360 


Zanesville 


Ohio 360 


Washington 


D.C. 360 


Memphis 


Tenn. 360 


Hamilton 


Ohio 360 


Schenectady 


N.Y. 360 


Urbana 


111. 360 


Camden 


N.J. 360 


Dallas 


Tex. 860-485 


Tarrytown 


N.Y. 360 


Atlanta 


Ga. 860-485 


Utica 


N.Y. 360 



m RADIO FOR ALL 


Call 






Wave- 


Letters 


Name 


City 


State Length 


WSN 


Ship Owners' Radio Ser- 








vice 


Norfolk 


Va. 860 


wsv 


L. M. Hunter & G. L. 








Carrington 


Little Rock 


Ark. 360 


wsx 


Erie Radio Co. 


Erie 


Pa. 360 


WSY 


Alabama Power Co. 


Birmingham 


Ala. 360 


WTG 


Kansas State Agric. Col- 








lege 


Manhattan 


Kans. 485 


WTK 


Paris Radio Electric Co. 


Paris 


Texas 360 


WTP 


George M. McBride 


Bay City 


Mich. 360 


WWB 


Daily News Printing Co. 


Canton 


Ohio 360 


WWI 


Ford Motor Co. 


Dearborn 


Mich. 360 


WWJ 


Detroit News 


Detroit 


Mich.360-485 


WWL 


Loyola University 


New Orleans 


La. 360 


WWT 


McCarthy Bros. & Ford 


Buffalo 


N.Y. 360 


WWZ 


John Wanamaker 


New York 


N.Y. 360 


CANADIAN BROADCASTING STATIONS 


Call 






Wave- 


Letters 


Name 


City 


Province Length 


CFAC 


Calgary Daily Herald 


Calgary 


Alta. 


CFCA 


Toronto Daily Star 


Toronto 


Ont. 420 


CFCB 


Daily Province 


Vancouver 


B.C. 440 


CHCF 


Marconi W. Co. of Can., 








Ltd. 


Montreal 


Que. 440 


CHBC 


The Morning Albertan 


Calgary 


Alta. 410 


CHCB 


Marconi Co. 


Toronto 


Ont. 440 


CHVC 


Metropolitan Motors Co. 


Toronto 


Ont. 420 


CJCA 


Edmonton Journal 


Edmonton 


Alta. 420 


CJCB 


News Publishing Co., 








Ltd. 


Nelson 


B.C. 420 


CJCD 


T. Eaton Co. 


Toronto 


Ont. 410 


CJCF 


Daily Record 


Kitchener 


Ont. 


CJGC 


London Free Press 


London 


Ont. 


CJNC 


Tribune Newspaper Co. 


Winnipeg 


Man. 420 


CKAC 


La Presse 


Montreal 


Quebec 430 


CKCE 


Can. Independent Tel. Co. 


Toronto 


Ont. 450 


CKCK 


Regina Leader 


Regina 


Sask. 420 


3JZ 


Marconi W. Tel. Co. 


Toronto 


Ont. 1200 



1 VANCOUVER, B.C. 




CALGARY, ALBERTA 



NORTH 
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! PA 



'RAPID CITY 

VERMIUOf 

RUSHVILLE ""' 



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| WICHITA-, 



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LOS ANGELES - A^ PASADENA ' 
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SAN DIEGO- 



'PHOEN/X " -"* 



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ROSVVELL 



AMARlLLO ! 

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WASHBURNJ OKLAHOM/! 



U.S. RADIOPHONE 
BROADCASTING STATIONS 

CORRECTED TO JUNE,30,!922 



AUSTIf 
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INDEX 



"A" Battery, 223 
Abbreviations, 242, 247 
Accessories Vacuum Tube, 85 
Aerial, 20, 21, 30, 31, 32, 83, 47, 

106, 108, 110, 112, 117, 121, 

122, 125, 127, 128, 130, 131, 

132, 137, 231, 250 
Aerial, Concealed, 231 
Aerial Circuit, 106 
Aerial Dimensions, 250 
Aerial, Four-wire, 110, 117 
Aerial, Height of, 112 
Aerial Indoor, 33 
Aerial, Inverted L, 132 
Aerial, Outdoor, 47 
Aerial, Single, 110, 121 
Aerial, Single-wire, 121 
Aerial, T Type, 131 
Aerial, Two- and Four-wire, 116 
Aerial, Umbrella, 122 
Aerial, Underground, 128, 129 % 

230 

Aerials, Loop, 108, 125, 127, 250 
Aerials, T, 131 

Aerials, Wave Lengths of, 130 
Ampere, 254 
Amplification, 46 
Amplification, Audio, 93 
Amplifier, 45, 69, 87, 96, 98, 170, 
Amplifier Rheostat, 226 

220, 226 

Amplifier, Two-Stage, 220 
Amplifier, Two-Step, 87 
Amplifier, Voice, 170 
Amplifiers, Audio Frequency, 96 
Amplifiers, Tone, 98 
Amplify, 86 



Amplifying Transformers, 224 
Analogy in Tuning, 104 
Antenna, 31, 142, 117, 119, 142, 

199, 250 

Antenna Connector, 117, 119 
Antenna, Transmitting Stations, 
Antennae, Loop, 250 
Arc, Electric, 37, 164, 165 
Arc Transmitted, 165 
Argentiferous Galena, 63 
Arresters, Lightning, 139 
Atmospheric Electricity, 37, 49, 

60, 66, 130, 139, 142 
Audio Amplification, 93 
Audio Frequency Amplifiers, 96 
Audio Frequency Transformer, 

88, 90 

Audion, 43, 66, 194 
Audion Bulb, 209 

"B" Battery, 89, 211, 223, 225 
Bakelite, 205, 212 
Bakelite Dials, 212 
Bakelite Panel, 209 
Balanced Circuit, 73 
Balls, Zinc, 30 
Bank-wound Coil, 209 
Battery "A," 223 
Bell, 19, 23 
Bell, Ringing, 19 
Binding Posts, 198, 208, 222 
Bornite, 62 

Broadcasted Entertainment, 174 
Broadcasting, 20, 27, 43, 168, 170, 
174, 177, 239, 244, 263, 266, 267 
Broadcasting Hour, 240, 244 
Broadcasting Music, 174 



284 



INDEX 



Broadcasting Station, 20, 27, 43, 
168, 170, 174, 239, 263, 266, 
277 

Broadcasting Stations, Cana- 
dian, 277 

Broadcasting Stations, U. S., 266 

Broad Interfering Wave, 261 

Bulb, Audion, 209 

Buzzer, 190, 193, 197 

Buzzer, Test, 197 

Call Letters, 240, 244 
Canadian Broadcasting Stat- 
ions, 277 
Candle, 44 

Capacity, 196, 249, 253, 254 
Capacity, Condenser, 196, 253 
Carbona, 64 
Carbon Detector, 53 
Carbon Tetrachloride, 64 
Carborundum Crystal, 58 
Carborundum Detector, 68 
Cardboard Tubes, 214 
Carrier Wave, Radio, 25 
Catwhisker, 62, 65, 66, 184 
Cell, 234 

Cells, Photo-Electric, 234, 236 
Charts, 131 
Circuit, Aerial, 106 
Circuit, Balanced, 73 
Circuit, Oscillating, 165 
Circuits, 149 

Clamp, Ground, 133, 134, 136 
Close Wave Length, 77 
Code, 34, 35, 36, 42, 247 
Code, Continental, 34 
Code, Radio, 247 
Code, Telegraphic, 34, 86 
Codes, Wireless, 35 
Coherer, 12, 40, 43, 51, 63 
Coherer, Marconi, 43, 53 
Coil, 187, 192, 196, 209 



Coil, Bank-wound, 209 

Coil Data, Tuning, 257 

Coil, Loop, 209 

Coil, Secondary, 192, 217 

Coil, Sending Tuning, 33 

Coil, Spark, 11, 30, 40 

Coil, Tap, 182 

Coil, Tickler, 226 

Coil, Tuning, 83, 84, 70, 71, 73, 

207 

Coils, 214, 217 
Cold Plate, 68 

83, 107, 196 
Compass, Radio, 126 
Compass Station, 125 
Concealed Aerial, 231 
Condenser Capacity, 196, 253 
Condenser, Fixed, 81, 85, 195, 

207 

Condenser, Grid, 210, 225 
Condenser, Grid Leak, 93 
Condenser, Phone, 84 
Condenser Plugs, 231, 232 
Condenser, Stopping, 207 
Condenser, Variable, 82, 83, 85, 

107, 138, 195, 208, 209 
Condensers, 79, 80, 81, 82, 83, 84, 

85, 93, 106, 107, 138, 189, 195, 

196, 207, 208, 209, 210, 225, 249 
Connector, Antenna, 117, 119 
Constants, Dielectric, 249, 252 
Continental Code, 34 
Continuous Waves, 13, 25, 37, 38, 
Cooper Wire Tables, 255 
Copper Pyrite, 62 
Copper-clad Wire, 109 
Cotton, Double Wire, 256 
Cotton-covered Magnet Wire, 

Double, 257 

Cotton, Single Wire, 256 
Coulomb, 254 
Coupler, Vario-, 79, 212 



INDEX 



285 



Couplers, Loose, 73, 75, 76, 77 

212, 216, 217, 218 
Crystal, 64, 65, 184, 189, 197, 199, 

203 

Crystal, Carborundum, 68 
Crystal Detector, 43, 58, 68, 72 
Crystal Outfit, 180 
Crystal Pressure, 59 
Current, 254 
Currents, High Frequency, 68, 

73 
Currents, Voice, 170 

Data, Tuning Coil, 257 

De Forest, 68 

Detectors, 40, 43, 44, 53, 54, 56, 

67, 58, 59, 60, 63, 68, 72, 193, 

197, 202 

Detector, Carbon, 63 
Detector, Carborundum, 58 
Detector, Crystal, 43, 58, 68, 72 
Detector, Electrolytic, 54, 56, 57 
Detector, Radiocite, 63 
Detector, " Rasco," 199 
Detector, Silicon, 69, 60, 61 
Detector, Vacuum Tube, 44 
Device, Protective, 141, 146 
Devices, Tuning, 70 
Diagnosis, Radio, 230 
Diagram, Radio, 149 
Diagrams, 149 
Dials, Bakelite, 212 
Diaphragm, 97 
Dielectric, 249 

Dielectric Constants, 249, 252 
Dimensions, Aerial, 250 
Distance, 27 

Distance, Transmitting, 40 
Distress Signals, 24, 35, 261 
Distress Wave, Standard, 261 
Division of Time, 262 
Double Cotton-covered Magnet 

Wire, 257 



Double Cotton Wire, 256 
Double Silk Wire, 256 
Doughnut Type Coil, 192 
Dunwoody, 68 

Edison, 66, 67 

Edison Effect, 67 

Effect, Inductive, 73 

Effect, Regenerative, 226 

Efficient Receiver, 206 

Electric Arc, 37, 164, 165 

Electric Cells, Photo-, 234, 236 

Electric Spark, 11 

Electric Waves, 11 

Electrical Microphones, 21, 165, 

166, 173, 174, 178 
Electrical Units, 254 
Electricity, Atmospheric, 37, 49, 

60, 66, 130, 139 
Electricity, Static, 37, 49, 50, 66, 

130, 139, 142 

Electro-Motive-Force, 254 
Electrolytic Detector, 54, 5, 57 
Electrons, 67, 68, 91 
E. M. F., 254 
Enameled Wires, 201, 256 
Entertainment, Broadcasted, 174 
Eternal Radio Waves, 237 

Fading Signals, 115 
Farad, 254 

Fessenden, Reginald, 166 
Filament, 67, 68, 69, 90, 209, 223 
Filament Voltage, 224 
Filings, 62 

Fixed Condenser, 81, 85, 195, 207 
Fleming, 68 

Force, Electro-Motive, 254 
Formica, 205 
Forms, 214 

Four-wire Aerial, 110, 117 
Frequencies, Wave Lengths and, 
251 



286 



INDEX 



Frequency Amplifiers, Audio, 94 
Frequency Currents, High, 68, 

73 
Frequency Transformer, Audio, 

88, 90 
Frequency Transformer, Radio, 

93, 94 

Fundamental Note, 81 
Future of Radio, 229 

Galena, Argentiferous, 63 

Galena, 63, 193, 197, 199, 203, 207 

Gap, Quenched Spark, 37 

Gauge, 255 

General Receiving, 42 

General Transmitting, 80, 37, 40 

Government Stations, 263 

Grand Opera by Wireless, 178 

Grid, 67, 69, 223 

Grid Condenser, 210, 226 

Grid Leak, 91, 92, 225 

Grid Leak Condenser, 93 

Ground, 202 

Ground Clamp, 133, 134, 136 

Ground, Operating, 144 

Ground Wire, 134, 141, 142, 143, 
144, 147 

Ground Wire, Operating, 144 

Ground Wire, Protective, 143, 
147 

Ground Wire, Receiving Equip- 
ment, 147 

Grounding Rod, 136 

Grounding Switch, Protective, 
143, 147 

Grounds, 108, 133, 136 

Height of Aerial, 112 

Henry, 264 

High Frequency Currents, 68, 

73 
High Power, 44 



Honeycomb, 209 

Hour, Broadcasting, 240, 244 

Impure Wave, 31 

Indoor, 33 

Inductance, 203, 204, 253, 254 

Inductive Effect, 73 

Information, Radio, 239 

Instruments, Receiving, 51 

Insulated, 256 

Insulators, 112, 118 

Intensity, 125 

Intensity Scale, Wind, 244 

Intercommunication, 202 

Interference, 76, 123 

Interfering Wave, Broad, 2fll 

Interrupted Spark Wave, 13, 38, 

39 

Interrupted Waves, 13, 38, 39, 
Inverted L Aerial, 132 
Inverted L Type, 116 
Invisible Sound Waves, 18 
Iron Pyrite, 62 

Jacks, 225 
Joule, 254 
Jumper Wire, 223 

Key, 24, 34 
Kilowatt, 39, 254 

"L," 250 

L Aerial, Inverted, 132 

L Type, Inverted, 116 

Law of 1912, Radio, 258 

Lead-in, 110, 119, 120, 141, 142, 

146, 201 

Lead-in Wires, 141, 142, 146, 201 
Leak, Grid, 91, 92, 225 
Length, Wave, 22, 23, 27, 84, 70, 

77, 105, 130, 131, 244, 250, 251, 



INDEX 



287 



Letters, Call, 240 244 

Lattice Type, 209 

Lightning Arresters, 139 

Lightning Regulations, 140 

Litz Wire, 209 

Locate Ores, Radio to, 230 

Loop, 231 

Loop Aerials, 108, 125, 127, 250 

Loop Antennae, 250 

Loop Coil, 209 

Loops, Underground, 230 

Loose Couplers, 73, 75, 76, 77, 212 

216, 217, 218 
Loud Speakers, 98 
Low Priced Receiving Set, 193 

Magnavox, 97, 226 
Magnet Wire, 256 
Magnet Wire, Double Cotton- 

256 
Marconi, Guglielmo, 12, 31, 34, 36 

37, 43, 52, 63 
Marconi Coherer, 53 
Market Reports, 244 
Meg-Ohm, 254 

covered, 257 

Messages, Secrecy of, 264 
Metal Pellet, 65 
Meter, 22 
Mica, 252 

Micro-farads, 249, 254 
Microphones, Electrical, 21 
Micro-watt, 254 
Milli-ampere, 254 
Milli-henry, 254 
Milli-Volt, 254 
Mineral, 62 

Misconception, Radio, 27 
Modulator, 234 
Modulator Tube, 171 
Motive-Force, Electro-, 254 
Music, Broadcasting, 174 



Music, Radio, 175 
Natural Wave Lengths, 131 
Night Time Reception, 48 
1912, Radio Law of, 258 
Normal Wave Length, 260 
Note, Fundamental, 31 

Ohm, 254, 255 

$1.00 Radio Set, 198 

Opera by Wireless, Grand, 178 

Operating Ground, 144 

Operating Ground Wire, 144 

Ores, Radio to Locate, 230 

Oscillating Circuit, 165 

Oscillations, 251 

Oscillator, 171 

Outdoor Aerial, 47 

Outfit, Crystal, 180 

Outfits, Simple Receiving, 180 

Panel, 212, 223 

Panel, Bakelite, 209 

Paper, Paraffined, 195 

Paraffined Paper, 195 

Pellet, Metal, 65 

Penalties, 265 

Performances, Radio, 177 

Phone Condenser, 84 

Photo-Electric Cells, 234, 236 

Pickard, Greenleaf W., 62, 

Picture Transmission, Radio, 233 

Pictures, Radio Sending, 232 

Pipe, Water, 106 

Plate, 67, 68, 69, 223 

Plate, Cold, 68 

Plug, 231 

Plugs, Condenser, 231, 232 

Pocket Size Receiving Set, 192 

Points, Sensitive, 63 

Points, Switch, 207 

Poles, 112 

Portable Receiving Set, 208, 209 

Posts, Binding, 198, 208, 222 



288 



INDEX 



Potentiometer, 66 
Poulsen, Valdemar, 13, 164 

165 

Power, 39, 40, 41, 44 
Power, High, 44 
Power Transmission, Radio, 232 
Press Schedules, 245 
Pressure, Crystal, 59 
Primaries, 215, 217, 218 
Primary, 75, 76, 192 
Principle of Transformer, 73 
Private Stations, 263 
Prospecting, Radio, 230 
Protective Device, 141, 146 
Protective Ground Wire, 143, 

147 
Protective Grounding Switch, 

143, 147 
Pure Wave, 261 
Pyrite, Copper, 62 
Pyrite, Iron, 62 

Quenched Spark Gap, 37 

Radio Carrier Wave, 25 

Radio Code, 247 

Radio Compass, 126 

Radio Diagnosis, 230 

Radio Diagrams, 149 

Radio Frequency Transformer, 

93, 94 

Radio, Future of, 229 
Radio Law of 1912, 258 
Radio Music, 175 
Radio Performances, 177 
Radio Picture Transmission, 133 
Radio Power Transmission, 232 
Radio Prospecting, 230 
Radio Sending Pictures, 232 
Radio Set, $1.00, 198 
Radio Signals, 46 
Radio Telephone, 166, 167 
Radio Telephone Daily, 229 



Radio Telephony, 42, 164, 166, 

167 

Radio Television, 234 
Radio to Locate Ores, 230 
Radio Wave, 14, 21, 26, 27, 34, 

232, 237, 261 

Radio Waves, Eternal, 237 
Radiocite, 62 
Radiocite Detector, 63 
Radiophone Receiver, Simple, 

185 

Radiophone Receiver, Simplest, 
"Radioson" Detector, 57 
Receiver, Efficient, 205 
Receiver, Simple Radiophone, 

181 
Receiver, Simplest Radiophone, 

181 

Receiver, Short Wave Regen- 
erative, 211 

Receivers, Telephone, 66, 96 
Receiving Equipment Ground 

Wire, 147 

Receiving (General), 42 
Receiving Instruments, 51 
Receiving Outfits, Simple, 180 
Receiving Set, 47, 192, 193, 208, 

209 

Receiving Set, Low-priced, 193 
Receiving Set, Pocket Size, 192 
Receiving Set, Portable, 208, 209 
Receiving Station, 42 
Receiving Transformer, 192 
Reception, Night Time, 48 
Rectifier, 85 

Regenerative Effect, 226 
Regenerative Receiver, Short 

Wave, 211 

Regulations, Lightning, 140 
Reports, Market, 244 
Reports, Weather, 240, 242, 243 
Restrictions, 263 



INDEX 



Resistance, 254 
Rheostat, 90, 209, 222 
Rheostat, Amplifier, 226 
Rheostats, 90, 209, 222 
Ring Wound Coil, 192 
Ringing Bell, 19 
Rod, Grounding, 136 
Rotor, 79 

Scale, Wind Intensity, 244 

Schedule, 240 

Schedules, Press, 245 

Secondary, 75, 76, 192, 215, 216, 
218 

Secondaries, 216, 218 

Secondary Coil, 192, 217 

Secrecy of Messages, 264 

Sending, 33, 39 

Sending Pictures, Radio, 232 

Sending Station, 27 

Sending Tuning Coil, 33 

Sensitive Points, 63 

Sensitivity, 44, 62 

Set, $1.00 Radio, 198 

Set, Low-priced Receiving, 193 

Set, Pocket Size Receiving, 192 

Set, Portable Receiving, 208 

Set, Receiving, 47, 192, 193, 198, 
208 

Sharp Tuning, 226 

Sharp Wave, 261 

Shellac, 188, 216 

Short Wave, 211 

Short Wave Regenerative Re- 
ceiver, 211 

Signals, Distress, 24, 35, 261 

Signals, Fading, 115 

Signals, Radio, 46 

Signals, Telegraphic, 24 

Signals, Time, 240 

Silk, Double Wire, 256 

Silk, Single Wire, 256 
19 



Silicon Detector, 59, 60, 61 
Simple Radiophone Receiver, 

185 

Simple Receiving Outfits, 180 
Simplest Radiophone Receiver, 
Simple Tuner, 203 

181 

Single Aerial, 110, 121 
Single Cotton Wire, 256 
Single Silk Wire, 256 
Single Vacuum Tube, 46 
Single-wire Aerial, 121 
Slider, 33, 70, 71, 72, 75, 102 
Slider, Tuning Coil, 102 
Socket, 209, 224, 225 
Solenoid, 253 
SOS, 24 
Sound, 20, 42 
Sound Waves, 16, 26 
Sound Waves, Invisible, 18 
Space, 23 

Spark Coil, 11, 30, 40 
Spark, Electric, 11, 30, 36 
Spark Gap, Quenched, 37 
Spark Stations, 245 
Spark Wave, Interrupted, 39 
Speakers, Loud, 97 
Speed of Waves, 26 
Spheres, 17 
Splices, 140 
Spreader, 118 

Standard Distress Wave, 261 
Static, 37, 49, 50, 66, 130, 139 
Static Electricity, 37, 49, 50, 66, 

130, 139 

Static Surges, 66 
Station, Broadcasting, 20, 27, 43, 

168, 170, 174, 239, 263, 266, 

277 

Station, Compass, 125 
Station, Receiving, 42 



290 

Station, Sending, 27 



Stations, Government, 263 

Stations, Private 263 

Stations, Spark, 245 

Stator, 79 

Step, Three-, 69 

Step, Two-, 69 

Stopping Condenser, 207 

Super-amplifier, 45 

Surges, 144, 148 

Surges, Static, 66 

Switch, 212 

Switch Points, 207 

Switch, Protective Grounding, 

143, 147 
Symbols, 158 

T Aerials, 131 

T Type Aerial, 131 

Tables, Cooper Wire, 255 

Tap Coil, 182 

Taps, 75 

Telegraphic Code, 34, 36 

Telegraphic Signals, 24 

Telemegaphone, 226 

Telephone Daily, Radio, 229 

Telephone, Radio, 42, 164, 166, 

167 

Telephone Receivers, 56, 96 
Telephone Transmitter, 166 
Telephony, Radio, 42, 164, 166, 

167 

Television, 233 
Television, Radio, 234 
Test Buzzer, 197 
Tetrachloride, Carbon, 64 
Three-Slide Tuners, 73 
Three-Step, 69 
Tickler, 223 



INDEX 

Tickler Coil, 226 

Time, Division of, 262 

Time Signals, 239 

Tinfoil, 195, 197 

Tone Amplifiers, 98 

Transformer, Audio Frequency, 



Transformer, Principle of, 73 
Transformer, Radio Frequency, 

93, 94 

Transformer, Receiving, 192 
Transformers, Amplifying, 224 
Transmission, Radio Picture, 233 
Transmission, Radio Power, 232 
Transmitter, 40, 165, 166, 
Transmitter, Arc, 165 
Transmitter, Telephone, 166 
Transmitters of Waves, 18 
Transmitting Distance, 40 
Transmitting (General), 30, 37 

40 
Transmitting Stations Antenna, 

142 

Transmitting Tubes, 171 
Trough, 23 

Tube Accessories, Vacuum, 85 
Tube, Modulator, 171 
Tube, Vacuum, 43, 46, 66, 67, 

68, 69, 85, 171 
Tubes, Cardboard, 214 
Tubes, Transmitting, 171 
Tuned, 28 
Tuner, Simple, 203 
Tuners, Three-Slide, 73 
Tuning, 32, 70, 73, 76, 77, 101, 

104 

Tuning, Analogy in, 104 
Tuning Coil, 33, 34, 70, 71, 73, 83, 

102, 103, 107, 196, 207, 257 



INDEX 



291 



Tuning Coil Data, 257 
Tuning Coil, Sending, 33 
Tuning Coil Slider, 102, 103 
Tuning Devices, 70 
Tuning Out, 28 
Tuning, Sharp, 76, 77, 226 
Two- and Four-wire Aerial, 116 
Two-Stage Amplifier, 220 
Two-Step, 69 
Two-Step Amplifier, 87 
Type, Coil Doughnut, 192 
Type, Inverted L, 116 
Type, Lattice, 209 

Umbrella Aerial, 122 
Underground Aerial, 128, 129, 

230 

Underground Loops, 230 
Units, Electrical, 254 
U. S. Broadcasting Stations, 266 

Vibrations, 25, 42 

Vacuum, 69 

Vacuum Tube, 43, 46, 66, 67, 68, 

69, 85, 171 

Vacuum Tube Accessories, 85 
Vacuum Tube Detector, 44, 
Vacuum Tube, Single, 46 
Values, Variocoupler, 258 
Valve, 68 
Variable Condenser, 82, 83, 85, 

107, 138, 195, 208, 209 
Vario-coupler, 79, 212 
Variocoupler Values, 258 
Variometers, 78, 212, 215, 216, 

218 

Voice Amplifier, 170 
Voice Currents, 170 
Volt, 254 
Voltage, Filament, 224 



Water Pipe, 106 

Water Waves, 16 

Watt, 254 

Wave, Broad Interfering, 261 

Wave, Impure, 31 

Wave Interrupted Spark, 89 

Wave Length, 22, 23, 27, 34, 70 

77, 105, 130, 131, 244, 250, 251, 

260 

Wave Length, Close, 77 
Wave Length, Normal, 260 
Wave Lengths of Aerials, 130 
Wave Lengths and Frequencies, 

251 

Wave Lengths, Natural, 131 
Wave, Pure, 261 
Wave, Radio, 14, 21, 26, 27, 34, 
Wave, Radio Carrier, 25 
Wave, Sharp, 261 
Wave, Short, 211 
Wave, Standard Distress, 261 
Wavelets, 37 
Waves, 11, 13, 14, 16, 18, 21, 25, 

26, 27, 31, 34, 37, 38, 39, 43, 47 

130, 131, 165, 211, 244, 250, 251, 

260, 261 
Waves, Continuous, 13, 25, 37, 38, 

165 

Waves, Electric, 11 
Waves, Eternal Radio, 237 
Waves, Interrupted, 13, 38 
Waves, Invisible Sound, 18 
Waves, Radio, 232, 237 
Waves, Sound, 16, 26 
Waves, Speed of, 26 
Waves, Transmitters of, 18 
Waves, Water, 16, 237, 261 
Weather Reports, 240, 242, 243 
Winding, 207, 216 
Wind Intensity Scale, 244 



INDEX 



Wire, Copper-clad, 109 

Wire, Double Cotton-covered 

Magnet, 257 
Wire, Enameled, 256 
Wire, Ground, 134, 141, 142, 143, 
Wireless Codes, 35 
Wireless, Grand Opera by, 178 
Wire, Litz, 209 
Wire, Magnet, 256 
Wire, Operating Ground, 144 

147 
Wire, Protective Ground, 143, 



Wire, Receiving Equipment 

Ground, 147 
Wires, Enameled, 201 
Wires, Lead-in, 141, 142, 146, 201 
Wire Tables, Cooper, 255 
Wire, Wollaston, 54, 56, 57 

144, 147 
Wiring, 225 

Wollaston Wire, 54, 56, 57 
Wound, Ring Coil, 192 

Zinc Balls, 30 



This book is DUE on the last date stamped below. 

| ~" 




TK 

6550 

G319r 



AA 000972755 3